Ordered delinquency: the "effects" of birth order on delinquency.
Cundiff, Patrick R
2013-08-01
Juvenile delinquency has long been associated with birth order in popular culture. While images of the middle child acting out for attention or the rebellious youngest child readily spring to mind, little research has attempted to explain why. Drawing from Adlerian birth order theory and Sulloway's born-to-rebel hypothesis, I examine the relationship between birth order and a variety of delinquent outcomes during adolescence. Following some recent research on birth order and intelligence, I use new methods that allow for the examination of between-individual and within-family differences to better address the potential spurious relationship. My findings suggest that contrary to popular belief, the relationship between birth order and delinquency is spurious. Specifically, I find that birth order effects on delinquency are spurious and largely products of the analytic methods used in previous tests of the relationship. The implications of this finding are discussed.
Examining the effects of birth order on personality.
Rohrer, Julia M; Egloff, Boris; Schmukle, Stefan C
2015-11-17
This study examined the long-standing question of whether a person's position among siblings has a lasting impact on that person's life course. Empirical research on the relation between birth order and intelligence has convincingly documented that performances on psychometric intelligence tests decline slightly from firstborns to later-borns. By contrast, the search for birth-order effects on personality has not yet resulted in conclusive findings. We used data from three large national panels from the United States (n = 5,240), Great Britain (n = 4,489), and Germany (n = 10,457) to resolve this open research question. This database allowed us to identify even very small effects of birth order on personality with sufficiently high statistical power and to investigate whether effects emerge across different samples. We furthermore used two different analytical strategies by comparing siblings with different birth-order positions (i) within the same family (within-family design) and (ii) between different families (between-family design). In our analyses, we confirmed the expected birth-order effect on intelligence. We also observed a significant decline of a 10th of a SD in self-reported intellect with increasing birth-order position, and this effect persisted after controlling for objectively measured intelligence. Most important, however, we consistently found no birth-order effects on extraversion, emotional stability, agreeableness, conscientiousness, or imagination. On the basis of the high statistical power and the consistent results across samples and analytical designs, we must conclude that birth order does not have a lasting effect on broad personality traits outside of the intellectual domain.
The confluence model: birth order as a within-family or between-family dynamic?
Zajonc, R B; Sulloway, Frank J
2007-09-01
The confluence model explains birth-order differences in intellectual performance by quantifying the changing dynamics within the family. Wichman, Rodgers, and MacCallum (2006) claimed that these differences are a between-family phenomenon--and hence are not directly related to birth order itself. The study design and analyses presented by Wichman et al. nevertheless suffer from crucial shortcomings, including their use of unfocused tests, which cause statistically significant trends to be overlooked. In addition, Wichman et al. treated birth-order effects as a linear phenomenon thereby ignoring the confluence model's prediction that these two samples may manifest opposing results based on age. This article cites between- and within-family data that demonstrate systematic birth-order effects as predicted by the confluence model. The corpus of evidence invoked here offers strong support for the assumption of the confluence model that birth-order differences in intellectual performance are primarily a within-family phenomenon.
Birth order has no effect on intelligence: a reply and extension of previous findings.
Wichman, Aaron L; Rodgers, Joseph Lee; Maccallum, Robert C
2007-09-01
We address points raised by Zajonc and Sulloway, who reject findings showing that birth order has no effect on intelligence. Many objections to findings of null birth-order results seem to stem from a misunderstanding of the difference between study designs where birth order is confounded with true causal influences on intelligence across families and designs that control for some of these influences. We discuss some of the consequences of not appreciating the nature of this difference. When between-family confounds are controlled using appropriate study designs and techniques such as multilevel modeling, birth order is shown not to influence intelligence. We conclude with an empirical investigation of the replicability and generalizability of this approach.
Birth Order Effects on Holland Type, Occupational Interests, and Values.
Hartung, Paul J.; Leong, Frederick T. L.; Grotti, Shannon D.; Goh, David; Gaylor, Michael
This investigation examined in two different samples, whether only children differ significantly from firstborn and later-born children in terms of their vocational personality type as described in Holland's RIASEC model, occupational interests, and work values. Literature on family configuration and vocational behavior is reviewed, and current…
Middleborns disadvantaged? Testing birth-order effects on fitness in pre-industrial Finns.
Faurie, Charlotte; Russell, Andrew F; Lummaa, Virpi
2009-05-25
Parental investment is a limited resource for which offspring compete in order to increase their own survival and reproductive success. However, parents might be selected to influence the outcome of sibling competition through differential investment. While evidence for this is widespread in egg-laying species, whether or not this may also be the case in viviparous species is more difficult to determine. We use pre-industrial Finns as our model system and an equal investment model as our null hypothesis, which predicts that (all else being equal) middleborns should be disadvantaged through competition. We found no overall evidence to suggest that middleborns in a family are disadvantaged in terms of their survival, age at first reproduction or lifetime reproductive success. However, when considering birth-order only among same-sexed siblings, first-, middle- and lastborn sons significantly differed in the number of offspring they were able to rear to adulthood, although there was no similar effect among females. Middleborn sons appeared to produce significantly less offspring than first- or lastborn sons, but they did not significantly differ from lastborn sons in the number of offspring reared to adulthood. Our results thus show that taking sex differences into account is important when modelling birth-order effects. We found clear evidence of firstborn sons being advantaged over other sons in the family, and over firstborn daughters. Therefore, our results suggest that parents invest differentially in their offspring in order to both preferentially favour particular offspring or reduce offspring inequalities arising from sibling competition.
Cheng, C-C J; Wang, W-L; Sung, Y-T; Wang, Y-C; Su, S-Y; Li, C-Y
2013-11-01
A child's gender and ordinal position within a family have varied implications on his or her personality and cognitive development. However, little is known about whether or not parental educational level may moderate the effects of birth order and gender. Basic Competence Test (BCT) scores of 290,588 young adolescents aged 15-16 years in Taiwan were analysed. Parental educational level was calculated as the highest educational attainment of the subjects' parents. The multiple linear regression model was used to assess the modification effects of parental educational levels on the associations of interest. After controlling for covariates, we noted a clear inverse relationship between birth order and BCT scores in Mandarin, Mathematics and Science. Additionally, boys had significantly lower mean scores in Mandarin, but had significantly higher mean scores in both Mathematics and Science. We also found the significant interactive effects of birth order, gender and parental educational attainment on BCT scores, in which the birth order and gender effects were more evident in higher-educated families than in lower-educated ones. This large cohort study confirmed that both birth order and gender may pose independent influences on BCT scores; moreover, such influences are significantly modified by parental educational attainment. © 2012 John Wiley & Sons Ltd.
Middleborns disadvantaged? Testing birth-order effects on fitness in pre-industrial Finns.
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Charlotte Faurie
Full Text Available Parental investment is a limited resource for which offspring compete in order to increase their own survival and reproductive success. However, parents might be selected to influence the outcome of sibling competition through differential investment. While evidence for this is widespread in egg-laying species, whether or not this may also be the case in viviparous species is more difficult to determine. We use pre-industrial Finns as our model system and an equal investment model as our null hypothesis, which predicts that (all else being equal middleborns should be disadvantaged through competition. We found no overall evidence to suggest that middleborns in a family are disadvantaged in terms of their survival, age at first reproduction or lifetime reproductive success. However, when considering birth-order only among same-sexed siblings, first-, middle- and lastborn sons significantly differed in the number of offspring they were able to rear to adulthood, although there was no similar effect among females. Middleborn sons appeared to produce significantly less offspring than first- or lastborn sons, but they did not significantly differ from lastborn sons in the number of offspring reared to adulthood. Our results thus show that taking sex differences into account is important when modelling birth-order effects. We found clear evidence of firstborn sons being advantaged over other sons in the family, and over firstborn daughters. Therefore, our results suggest that parents invest differentially in their offspring in order to both preferentially favour particular offspring or reduce offspring inequalities arising from sibling competition.
Dunkel, Curtis S.; Harbke, Colin R.; Papini, Dennis R.
2009-01-01
The authors proposed that birth order affects psychosocial outcomes through differential investment from parent to child and differences in the degree of identification from child to parent. The authors conducted this study to test these 2 models. Despite the use of statistical and methodological procedures to increase sensitivity and reduce…
Appraising Birth Order in Career Assessment: Linkages to Holland's and Super's Models.
Leong, Frederick T. L.; Hartung, Paul J.; Goh, David; Gaylor, Michael
2001-01-01
Study 1 (n=159) found significant differences in vocational personality types, interests, and values depending on birth order. Study 2 (n=119) found significant differences in occupational interests by birth order. Both results support Alfred Adler's theory that birth order determines aspects of vocational behavior. (Contains 33 references.) (SK)
Appraising Birth Order in Career Assessment: Linkages to Holland's and Super's Models.
Leong, Frederick T. L.; Hartung, Paul J.; Goh, David; Gaylor, Michael
2001-01-01
Study 1 (n=159) found significant differences in vocational personality types, interests, and values depending on birth order. Study 2 (n=119) found significant differences in occupational interests by birth order. Both results support Alfred Adler's theory that birth order determines aspects of vocational behavior. (Contains 33 references.) (SK)
Birth order effects on the separation process in young adults: an evolutionary and dynamic approach.
Ziv, Ido; Hermel, Orly
2011-01-01
The present study analyzes the differential contribution of a familial or social focus in imaginative ideation (the personal fable and imagined audience mental constructs) to the separation-individuation process of firstborn, middleborn, and lastborn children. A total of 160 young adults were divided into 3 groups by birth order. Participants' separation-individuation process was evaluated by the Psychological Separation Inventory, and results were cross-validated by the Pathology of Separation-Individuation Inventory. The Imaginative Ideation Inventory tested the relative dominance of the familial and social environments in participants' mental constructs. The findings showed that middleborn children had attained more advanced separation and were lower in family-focused ideation and higher in nonfamilial social ideation. However, the familial and not the social ideation explained the variance in the separation process in all the groups. The findings offer new insights into the effects of birth order on separation and individuation in adolescents and young adults.
Family matters: effects of birth order, culture, and family dynamics on surrogate decision-making.
Su, Christopher T; McMahan, Ryan D; Williams, Brie A; Sharma, Rashmi K; Sudore, Rebecca L
2014-01-01
Cultural attitudes about medical decision-making and filial expectations may lead some surrogates to experience stress and family conflict. Thirteen focus groups with racially and ethnically diverse English and Spanish speakers from county and Veterans Affairs hospitals, senior centers, and cancer support groups were conducted to describe participants' experiences making serious or end-of-life decisions for others. Filial expectations and family dynamics related to birth order and surrogate decision-making were explored using qualitative, thematic content analysis, and overarching themes from focus group transcripts were identified. The mean age of the 69 participants was 69 ± 14, and 29% were African American, 26% were white, 26% were Asian or Pacific Islander, and 19% were Latino. Seventy percent of participants engaged in unprompted discussions about birth order and family dynamics. Six subthemes were identified within three overarching categories: communication (unspoken expectations and discussion of death as taboo), emotion (emotional stress and feelings of loneliness), and conflict (family conflict and potential solutions to prevent conflict). These findings suggest that birth order and family dynamics can have profound effects on surrogate stress and coping. Clinicians should be aware of potential unspoken filial expectations for firstborns and help facilitate communication between the patient, surrogate, and extended family to reduce stress and conflict.
Intelligence, birth order, and family size.
Kanazawa, Satoshi
2012-09-01
The analysis of the National Child Development Study in the United Kingdom (n = 17,419) replicates some earlier findings and shows that genuine within-family data are not necessary to make the apparent birth-order effect on intelligence disappear. Birth order is not associated with intelligence in between-family data once the number of siblings is statistically controlled. The analyses support the admixture hypothesis, which avers that the apparent birth-order effect on intelligence is an artifact of family size, and cast doubt on the confluence and resource dilution models, both of which claim that birth order has a causal influence on children's cognitive development. The analyses suggest that birth order has no genuine causal effect on general intelligence.
Zajonc, R. B.; And Others
1979-01-01
Discusses the controversy of the relationship between birth order and intellectual performance through a detailed evaluation of the confluence model which assumes that the rate of intellectual growth is a function of the intellectual environment within the family and associated with the special circumstances of last children. (CM)
Nuttall, Ena Vazquez; And Others
1976-01-01
Family constellation variables such as family size, birth order, spacing of children, and crowding were significantly associated with academic achievement when IQ was controlled. The effects of family constellation variables were found to be sex specific. (RC)
The Effects of Birth Order on Personality Traits and Feelings of Academic Sibling Rivalry
Badger, Julia; Reddy, Peter
2009-01-01
The influence of birth order on personality and sibling rivalry is controversial; little research has been conducted into academic sibling rivalry, and none into the connection with personality traits. This study considers the interaction of all three factors. Firstborns (N=22) and lastborns (N=24) completed online personality tests and an…
Born to learn or born to win? Birth order effects on achievement goals
Carette, Bernd; Anseel, Frederik; Van Yperen, Nico W.
2011-01-01
Given the widespread use and well-known consequences of achievement goals in different competence-relevant situations, it is important to gain a thorough understanding of how these differences in goal pursuit are formed. Using different analytic approaches, we show that birth order lies at the heart
Born to learn or born to win? Birth order effects on achievement goals
Carette, Bernd; Anseel, Frederik; Van Yperen, Nico W.
2011-01-01
Given the widespread use and well-known consequences of achievement goals in different competence-relevant situations, it is important to gain a thorough understanding of how these differences in goal pursuit are formed. Using different analytic approaches, we show that birth order lies at the heart
Birth order and human capital development: evidence from Ecuador
de Haan, M.; Plug, E.; Rosero, J.
2014-01-01
In this paper we examine the effect of birth order on human capital development in Ecuador. Using family fixed effects models we find positive and persistent birth order effects; earlier-born children stay behind in their human capital development from infancy to adolescence. Turning to potential me
Eyring, W E; Sobelman, S
1996-04-01
The purpose of this investigation was to clarify the relationship between birth-order position and the development of narcissism, while refining research and theory. The relationship between birth-order status and narcissism was examined with a sample of 79 undergraduate students (55 women and 24 men). These subjects were placed in one of the four following birth-order categories of firstborn, second-born, last-born, and only children. These categories were chosen given their significance in Adlerian theory. Each subject completed the Narcissistic Personality Inventory and a demographic inventory. Based on psychodynamic theory, it was hypothesized that firstborn children were expected to score highest, but statistical significance was not found for an association between narcissism and birth order. Further research is urged to investigate personality theory as it relates to parenting style and birth order.
Methodology, Birth Order, Intelligence, and Personality.
Michalski, Richard L.; Shackelford, Todd K.
2001-01-01
Critiques recent research on the effects of birth order on intelligence and personality, which found that the between-family design revealed that birth order negatively related to intelligence, while the within-family design revealed that birth order was unrelated to intelligence. Suggests that it may not be intelligence that co-varies with birth…
Birth Order and Psychopathology
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Ajay Risal
2012-01-01
Full Text Available Context: Ordinal position the child holds within the sibling ranking of a family is related to intellectual functioning, personality, behavior, and development of psychopathology. Aim: To study the association between birth order and development of psychopathology in patients attending psychiatry services in a teaching hospital. Settings and Design: Hospital-based cross-sectional study. Materials and Methods: Retrospective file review of three groups of patients was carried out. Patient-related variables like age of onset, birth order, family type, and family history of mental illness were compared with psychiatry diagnosis (ICD-10 generated. Statistical Analysis: SPSS 13; descriptive statistics and one-way analysis of variance (ANOVA were used. Results: Mean age of onset of mental illness among the adult general psychiatry patients (group I, n = 527 was found to be 33.01 ± 15.073, while it was 11.68 ± 4.764 among the child cases (group II, n = 47 and 26.74 ± 7.529 among substance abuse cases (group III, n = 110. Among group I patients, commonest diagnosis was depression followed by anxiety and somatoform disorders irrespective of birth order. Dissociative disorders were most prevalent in the first born child (36.7% among group II patients. Among group III patients, alcohol dependence was maximum diagnosis in all birth orders. Conclusions: Depression and alcohol dependence was the commonest diagnosis in adult group irrespective of birth order.
Strategic parenting, birth order, and school performance.
Hotz, V Joseph; Pantano, Juan
2015-10-01
Fueled by new evidence, there has been renewed interest about the effects of birth order on human capital accumulation. The underlying causal mechanisms for such effects remain unsettled. We consider a model in which parents impose more stringent disciplinary environments in response to their earlier-born children's poor performance in school in order to deter such outcomes for their later-born offspring. We provide robust empirical evidence that school performance of children in the National Longitudinal Study Children (NLSY-C) declines with birth order as does the stringency of their parents' disciplinary restrictions. When asked how they will respond if a child brought home bad grades, parents state that they would be less likely to punish their later-born children. Taken together, these patterns are consistent with a reputation model of strategic parenting.
Birth Order, Family Size and Educational Attainment
de Haan, Monique
2010-01-01
This paper investigates the effect of family size and birth order on educational attainment. An instrumental variables approach is used to identify the effect of family size. Instruments for the number of children are twins at last birth and the sex mix of the first two children. The effect of birth order is identified, by examining the relation…
Pedophilia, sexual orientation, and birth order.
Bogaert, A F; Bezeau, S; Kuban, M; Blanchard, R
1997-05-01
This study extended research on birth order and erotic preferences by examining birth order in a sample of pedophiles. Charts of 338 pedophiles, assessed from 1980-1994 in the Behavioural Sexology Department of the Clarke Institute of Psychiatry in Toronto, were reviewed for family-demographic information. In total, 170 (57 heterosexual pedophiles, 68 homosexual pedophiles, and 45 bisexual pedophiles) of these men had sufficient sibling information to be included in the analyses. The results indicated that homosexual-bisexual pedophiles had a later birth order than heterosexual pedophiles and that this effect was primarily the result of the homosexual-bisexual group being born later among their brothers. The results extend previous findings that homosexual men, regardless of sample composition, have a later birth order than comparable groups of heterosexual men. The results also challenge some existing theories on the nature and origins of pedophilia.
Someya, T; Uehara, T; Kadowaki, M; Tang, S W; Takahashi, S
2000-02-01
The relationship between Egna Minnen av Barndoms Uppforstran (EMBU) scaling and gender, birth order and parents' gender was previously investigated in a large volunteer sample; significant interactions among the variables were found. In the present study, 730 Japanese volunteers with one sibling were used as subjects in order to control the number of siblings: the effect of gender of subjects and siblings and birth order on the perceived parenting style was examined. Based on gender and birth orders, 730 subjects were grouped into the following categories: (i) male with a younger brother; (ii) male with a younger sister; (iii) male with an older brother; (iv) male with an older sister; (v) female with a younger brother; (vi) female with a younger sister; (vii) female with an older brother; and (viii) female with an older sister. One-way ANOVA was performed with each EMBU subscale used as a dependent variable and these eight groups as independent variables. The scores for rejection and emotional warmth of father were influenced significantly by the pattern of siblings (Pparenting style as more rejecting than others, and female children (elder sisters with brother, or younger sisters with sister) recognized parenting style as more caring and demonstrated more warmth than others. The results confirmed a significant interaction of gender of subjects and siblings and birth order of perceived parental rearing behavior.
Horner, Pilar; Andrade, Fernando; Delva, Jorge; Grogan-Kaylor, Andy; Castillo, Marcela
2012-01-01
Alfred Adler attempted to understand how family affects youth outcomes by considering the order of when a child enters a family (Adler, 1964). Adler's theory posits that birth order formation impacts individuals. We tested Adler's birth order theory using data from a cross-sectional survey of 946 Chilean youths. We examined how birth order and gender are associated with drug use and educational outcomes using three different birth order research models including: (1) Expedient Research, (2) Adler's birth order position, and (3) Family Size theoretical models. Analyses were conducted with structural equation modeling (SEM). We conclude that birth order has an important relationship with substance use outcomes for youth but has differing effects for educational achievement across both birth order status and gender.
Birth order, family size and educational attainment
de Haan, M.
2010-01-01
This paper investigates the effect of family size and birth order on educational attainment. An instrumental variables approach is used to identify the effect of family size. Instruments for the number of children are twins at last birth and the sex mix of the first two children. The effect of birth
Birth Order Positions and Personality Traits.
Tharbe, Ida Hartini Ahmad; Harun, Lily Mastura Hj.
The growing concern for the development of teenagers has brought up issues regarding the role of the family system in shaping the personality traits of children. Alfred Adler (1870-1937), an Austrian psychiatrist who introduced the psychological/therapeutic model, "Individual Psychology," highlighted the importance of birth order positions in…
What Research Shows About Birth Order, Personality, and IQ.
Yahraes, Herbert
This brief report summarizes the findings and conclusions of studies concerning the relation between birth order and various aspects of personality and intellectual development. Major topics discussed are the relation between birth order of the child and: (1) the effects of sex and spacing between siblings on personality characteristics of the…
Birth Order and Maladaptive Behavior in School-Aged Children.
Carmichael, Karla D.
Drawing on Alfred Adler's theories on the effect of birth order on maladaptive behavior in children, this study focused on the relationship between birth order and the referral to counseling of school-aged children with maladaptive disorder. School-aged children (N=217) with academic or behavioral problems, ages 5 to 18, were referred to the staff…
Birth Order and Maladaptive Behavior in School-Aged Children.
Carmichael, Karla D.
Drawing on Alfred Adler's theories on the effect of birth order on maladaptive behavior in children, this study focused on the relationship between birth order and the referral to counseling of school-aged children with maladaptive disorder. School-aged children (N=217) with academic or behavioral problems, ages 5 to 18, were referred to the staff…
Birth order, family size and school failure.
Belmont, L; Stein, Z A; Wittes, J T
1976-08-01
The effect of birth order on educational outcome in the Netherlands is reported for two major social classes, manual and non-manual. The rates of school failure (those who attended schools for the mentally retarded and who failed lower school) were studied in a population of some 200,000 young adult Dutch males born between 1944 and 1946 and whose families of origin had from one to six children. The data used were the records of the Dutch military pre-induction examination. Rates of school failure rose both with increased birth order and with increased family-size, with the exception of one-child families. School failure rates for the first, middle-and last-born were examined for the two social classes, with family size controlled. In general, school-failure rates were significantly related to birth-order position. For each family size and in both social classes, the last-born were at greater risk of school failure than were the first-born.
Birth order and neural tube defects: a reappraisal.
Vieira, Alexandre R
2004-01-15
There is evidence that late birth order is associated with some complex disorders. For neural tube defects (NTDs) there is no consensus as to whether first or increased birth order is associated or not. A meta-analysis of published data on NTDs was carried out to ascertain whether there is an increased risk for children first born or of high birth order to have NTDs. All data available with information regarding the frequency of live births and NTDs cases by birth order (1, 2, 3, and 4 or more) were included in the analysis. Effect sizes calculations were performed. Children with higher birth order are more likely to have spina bifida but not anencephaly. This same effect was also seen for all NTDs combined, which probably reflects the association with spina bifida. These results suggest the compilation of anencephaly and spina bifida data can be the explanation for the controversies seen in the literature.
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Ogbuanu Ikechukwu U
2010-04-01
Full Text Available Abstract Background Susceptibility to atopy originates from effects of the environment on genes. Birth order has been identified as a risk factor for atopy and evidence for some candidate genes has been accumulated; however no study has yet assessed a birth order-gene interaction. Objective To investigate the interaction of IL13 polymorphisms with birth order on allergic sensitization at ages 4, 10 and 18 years. Methods Mother-infant dyads were recruited antenatally and followed prospectively to age 18 years. Questionnaire data (at birth, age 4, 10, 18; skin prick test (SPT at ages 4, 10, 18; total serum IgE and specific inhalant screen at age 10; and genotyping for IL13 were collected. Three SNPs were selected from IL13: rs20541 (exon 4, nonsynonymous SNP, rs1800925 (promoter region and rs2066960 (intron 1. Analysis included multivariable log-linear regression analyses using repeated measurements to estimate prevalence ratios (PRs. Results Of the 1456 participants, birth order information was available for 83.2% (1212/1456; SPT was performed on 67.4% at age 4, 71.2% at age 10 and 58.0% at age 18. The prevalence of atopy (sensitization to one or more food or aeroallergens increased from 19.7% at age 4, to 26.7% at 10 and 41.1% at age 18. Repeated measurement analysis indicated interaction between rs20541 and birth order on SPT. The stratified analyses demonstrated that the effect of IL13 on SPT was restricted only to first-born children (p = 0.007; adjusted PR = 1.35; 95%CI = 1.09, 1.69. Similar findings were noted for firstborns regarding elevated total serum IgE at age 10 (p = 0.007; PR = 1.73; 1.16, 2.57 and specific inhalant screen (p = 0.034; PR = 1.48; 1.03, 2.13. Conclusions This is the first study to show an interaction between birth order and IL13 polymorphisms on allergic sensitization. Future functional genetic research need to determine whether or not birth order is related to altered expression and methylation of the IL13 gene.
Birth order and selected work-related personality variables.
Phillips, A S; Bedeian, A G; Mossholder, K W; Touliatos, J
1988-12-01
A possible link between birth order and various individual characteristics (e. g., intelligence, potential eminence, need for achievement, sociability) has been suggested by personality theorists such as Adler for over a century. The present study examines whether birth order is associated with selected personality variables that may be related to various work outcomes. 3 of 7 hypotheses were supported and the effect sizes for these were small. Firstborns scored significantly higher than later borns on measures of dominance, good impression, and achievement via conformity. No differences between firstborns and later borns were found in managerial potential, work orientation, achievement via independence, and sociability. The study's sample consisted of 835 public, government, and industrial accountants responding to a national US survey of accounting professionals. The nature of the sample may have been partially responsible for the results obtained. Its homogeneity may have caused any birth order effects to wash out. It can be argued that successful membership in the accountancy profession requires internalization of a set of prescribed rules and standards. It may be that accountants as a group are locked in to a behavioral framework. Any differentiation would result from spurious interpersonal differences, not from predictable birth-order related characteristics. A final interpretation is that birth order effects are nonexistent or statistical artifacts. Given the present data and particularistic sample, however, the authors have insufficient information from which to draw such a conclusion.
Biswas, Sadaruddin; Bose, Kaushik
2010-08-01
One of the greatest problems facing developing countries, including rural India, is undernutrition in terms of stunting among under 5-year-old children. However, there exists scanty information on the prevalence of stunting among preschool children in India and in particular in West Bengal. This study investigated prevalence of stunting and identified the predictor(s) of stunting among 1-5-year-old Bengalee rural preschool children of Integrated Child Development Services (ICDS) centres. This cross-sectional study was undertaken at different ICDS centres of Chapra Block, Nadia District, West Bengal, India. A total of 673 preschool children (323 boys and 350 girls), aged 1-5 years were selected from 30 randomly selected ICDS centres to study the impact of parents' educational status and child birth order on stunting. The overall (age and sex combined) rate of stunting was 39.2%. Child birth order (BO) (chi(2)=14.10, df=1, peducational status (FES) (chi(2)=21.11, peducational status (MES) (chi(2)=14.34, df=1, p>0.001) were significantly associated with the prevalence of stunting among girls. Logistic regression analyses revealed that both FES (Wald=19.97, por=3rd BO had significantly higher risk (OR=2.49, CI=1.54-4.03) of stunting than those with or=secondary level. Similarly, girls with MESor=secondary level. In conclusion our study revealed that BO as well as parents' educational status were strong predictors of stunting among girls but not boys. Sex discrimination could be a likely cause for this sex difference in the impact of BO and parents' educational status.
Sibship size, birth order, and personality.
Abdel-Khalek, Ahmed; Lester, David
2005-10-01
In a sample of 273 American college students who were administered seven personality tests, only death obsession scores were consistently associated with sibship size and birth order (not optimism, pessimism, anxiety, a Taoist orientation, suicidal ideation, or obsessive-compulsive tendencies).
Birth Order and Marital Bliss in Israel
Weller, Leonard; And Others
1974-01-01
This study offers a rank order of successful marriages, according to birth order in Israel. The results of two studies show that marriage consisting of a first born and a later born are more successful than marriages composed of two first borns or two later borns. (Author/PC)
Birth Order and Sibling Sex Ratio of Children and Adolescents Referred to a Gender Identity Service
Doug P Vanderlaan; Ray Blanchard; Hayley Wood; Kenneth J Zucker
2014-01-01
In adult male samples, homosexuality is associated with a preponderance of older brothers (i.e., the fraternal birth order effect). In several studies comparing gender dysphoric youth, who are likely to be homosexual in adulthood, to clinical or non-clinical control groups, the findings have been consistent with the fraternal birth order effect in males; however, less is known about unique sibship characteristics of gender dysphoric females. The current study investigated birth order and sibl...
Horner, Pilar; Andrade, Fernando; Delva, Jorge; Grogan-Kaylor, Andy; Castillo,Marcela
2012-01-01
Alfred Adler attempted to understand how family affects youth outcomes by considering the order of when a child enters a family (Adler, 1964). Adler’s theory posits that birth order formation impacts individuals. We tested Adler’s birth order theory using data from a cross-sectional survey of 946 Chilean youths. We examined how birth order and gender are associated with drug use and educational outcomes using three different birth order research models including: (1) Expedient Research, (2) A...
Birth order and its association with the onset of chronic fatigue syndrome.
Brimacombe, Michael; Helmer, Drew A; Natelson, Benjamin H
2002-08-01
Chronic fatigue syndrome (CFS) is a medically unexplained illness that is diagnosed on the basis of a clinical case definition; so it probably is an illness with multiple causes producing the same clinical picture. One way of dealing with this heterogeneity is to stratify patients based on illness onset. We hypothesized that either the whole group of CFS patients or that group which developed CFS gradually would show a relation with birth order, while patients who developed CFS suddenly, probably due to a viral illness, would not show such a relation. We hypothesized the birth order effect in the gradual onset group because those patients have more psychological problems, and birth order effects have been shown for psychological characteristics. We compared birth order in our CFS patients to that in a comparison group derived from U.S. demographic data. We found a tendency that did not reach formal statistical significance for a birth order effect in the gradual onset group, but not in either the sudden onset or combined total group. However, the birth order effect we found was due to relatively increased rates of CFS in second-born children; prior birth order studies of personality characteristics have found such effects to be skewed toward first-born children. Thus, our data do support a birth order effect in a subset of patients with CFS. The results of this study should encourage a larger multicenter study to further explore and understand this relation.
Gender Nonconformity and Birth Order in Relation to Anal Sex Role Among Gay Men.
Swift-Gallant, Ashlyn; Coome, Lindsay A; Monks, D Ashley; VanderLaan, Doug P
2017-04-04
Androphilia is associated with an elevated number of older brothers among natal males. This association, termed the fraternal birth order effect, has been observed among gay men who exhibit marked gender nonconformity. Gender nonconformity has been linked to gay men's preferred anal sex role. The present study investigated whether these two lines of research intersect by addressing whether the fraternal birth order effect was associated with both gender nonconformity and a receptive anal sex role (243 gay men, 91 heterosexual men). Consistent with previous research, we identified the fraternal birth order effect in our sample of gay men. Also, gay men were significantly more gender-nonconforming on adulthood and recalled childhood measures compared to heterosexual men. When gay men were compared based on anal sex role (i.e., top, versatile, bottom), all groups showed significantly greater recalled childhood and adult male gender nonconformity than heterosexual men, but bottoms were most nonconforming. Only gay men with a bottom anal sex role showed evidence of a fraternal birth order effect. A sororal birth order effect was found in our sample of gay men, driven by versatiles. No significant associations were found between fraternal birth order and gender nonconformity measures. These results suggest that the fraternal birth order effect may apply to a subset of gay men who have a bottom anal sex role preference and that this subgroup is more gender-nonconforming. However, there were no significant associations between fraternal birth order and gender nonconformity at the individual level. As such, based on the present study, whether processes underpinning the fraternal birth order effect influence gender nonconformity is equivocal.
Brief Report: Asperger's Syndrome and Sibling Birth Order
Schmidt, Karmen; Zimmerman, Andrew; Bauman, Margaret; Ferrone, Christine; Venter, Jacob; Spybrook, Jessaca; Henry, Charles
2013-01-01
Prior investigations suggest that birth order position may be associated with the risk for developing a pervasive developmental disorder. This retrospective chart review examined the birth order status of 29 psychiatrically-referred patients with Asperger's Syndrome (AS). Eighty-six percent of the subjects were first born. The finding was…
Brief Report: Asperger's Syndrome and Sibling Birth Order
Schmidt, Karmen; Zimmerman, Andrew; Bauman, Margaret; Ferrone, Christine; Venter, Jacob; Spybrook, Jessaca; Henry, Charles
2013-01-01
Prior investigations suggest that birth order position may be associated with the risk for developing a pervasive developmental disorder. This retrospective chart review examined the birth order status of 29 psychiatrically-referred patients with Asperger's Syndrome (AS). Eighty-six percent of the subjects were first born. The finding was…
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Feij, Jan A,
2010-12-01
Full Text Available Genetic analyses of sensation seeking have shown fairly high heritabilities for measures of this trait. However, 40 to 60% of the variance remains unexplained by genetic factors. This longitudinal study examines the influence of characteristics of the family environment -- birth order, family size, socio-economic status and parenting styles -- on two dimensions of sensation seeking: disinhibition and boredom susceptibility. Previous research has shown that these dimensions load on the same factor, are related to biologically based impulsive disorders, and have a common genetic basis. Questionnaire and biographical data obtained from 532 female and 479 male young adults (age between 18 and 30 years were analyzed using structural modeling. The results show that participants who experienced little parental care and much control were more likely to have high scores on disinhibition and boredom susceptibility. It appears that these family factors may partly explain the previously reported effects of birth order and family size on sensation seeking.
A multilevel approach to the relationship between birth order and intelligence.
Wichman, Aaron L; Rodgers, Joseph Lee; MacCallum, Robert C
2006-01-01
Many studies show relationships between birth order and intelligence but use cross-sectional designs or manifest other threats to internal validity. Multilevel analyses with a control variable show that when these threats are removed, two major results emerge: (a) birth order has no significant influence on children's intelligence and (b) earlier reported birth order effects on intelligence are attributable to factors that vary between, not within, families. Analyses on 7- to 8 - and 13- to 14-year-old children from the National Longitudinal Survey of Youth support these conclusions. When hierarchical data structures, age variance of children, and within-family versus between-family variance sources are taken into account, previous research is seen in a new light.
Fraternal birth order and sexual orientation in pedophiles.
Blanchard, R; Barbaree, H E; Bogaert, A F; Dickey, R; Klassen, P; Kuban, M E; Zucker, K J
2000-10-01
Whether homosexual pedophiles have more older brothers (a higher fraternal birth order) than do heterosexual pedophiles was investigated. Subjects were 260 sex offenders (against children age 14 or younger) and 260 matched volunteer controls. The subject's relative attraction to male and female children was assessed by phallometric testing in one analysis, and by his offense history in another. Both methods showed that fraternal birth order correlates with homosexuality in pedophiles, just as it does in men attracted to physically mature partners. Results suggest that fraternal birth order (or the underlying variable it represents) may prove the first identified universal factor in homosexual development. Results also argue against a previous explanation of the high prevalence of homosexuality in pedophiles (25% in this study), namely, that the factors that determine sexual preference in pedophiles are different from those that determine sexual preference in men attracted to adults. An alternative explanation in terms of canalization of development is suggested.
Earliest Recollections and Birth Order: Two Adlerian Exercises.
Parrott, Les
1992-01-01
Presents two exercises designed to demonstrate the influence of two Adlerian principles on personality. Includes exercises dealing with birth order and earliest recollection. Concludes that the exercises actively demonstrate major concepts for counseling courses in Adlerian psychotherapy. Reports that students rated both exercises highly, with…
Birth Order, Sibling IQ Differences, and Family Relations.
Pfouts, Jane H.
The differential impact of birth order and IQ on sibling roles were examined with particular interest focused on achievement outcomes. Subjects were a stratified sample of 37 pairs of near-in-age siblings, all within the normal range in personality and IQ, but differing significantly in scores on the Slosson IQ Test. Results indicate that when the…
Birth order and sibling sex ratio of children and adolescents referred to a gender identity service.
Vanderlaan, Doug P; Blanchard, Ray; Wood, Hayley; Zucker, Kenneth J
2014-01-01
In adult male samples, homosexuality is associated with a preponderance of older brothers (i.e., the fraternal birth order effect). In several studies comparing gender dysphoric youth, who are likely to be homosexual in adulthood, to clinical or non-clinical control groups, the findings have been consistent with the fraternal birth order effect in males; however, less is known about unique sibship characteristics of gender dysphoric females. The current study investigated birth order and sibling sex ratio in a large sample of children and adolescents referred to the same Gender Identity Service (N = 768). Probands were classified as heterosexual males, homosexual males, or homosexual females based on clinical diagnostic information. Groups differed significantly in age and sibship size, and homosexual females were significantly more likely to be only children. Subsequent analyses controlled for age and for sibship size. Compared to heterosexual males, homosexual males had a significant preponderance of older brothers and homosexual females had a significant preponderance of older sisters. Similarly, the older sibling sex ratio of homosexual males showed a significant excess of brothers whereas that of homosexual females showed a significant excess of sisters. Like previous studies of gender dysphoric youth and adults, these findings were consistent with the fraternal birth order effect. In addition, the greater frequency of only children and elevated numbers of older sisters among the homosexual female group adds to a small literature on sibship characteristics of potential relevance to the development of gender identity and sexual orientation in females.
Birth order and sibling sex ratio of children and adolescents referred to a gender identity service.
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Doug P Vanderlaan
Full Text Available In adult male samples, homosexuality is associated with a preponderance of older brothers (i.e., the fraternal birth order effect. In several studies comparing gender dysphoric youth, who are likely to be homosexual in adulthood, to clinical or non-clinical control groups, the findings have been consistent with the fraternal birth order effect in males; however, less is known about unique sibship characteristics of gender dysphoric females. The current study investigated birth order and sibling sex ratio in a large sample of children and adolescents referred to the same Gender Identity Service (N = 768. Probands were classified as heterosexual males, homosexual males, or homosexual females based on clinical diagnostic information. Groups differed significantly in age and sibship size, and homosexual females were significantly more likely to be only children. Subsequent analyses controlled for age and for sibship size. Compared to heterosexual males, homosexual males had a significant preponderance of older brothers and homosexual females had a significant preponderance of older sisters. Similarly, the older sibling sex ratio of homosexual males showed a significant excess of brothers whereas that of homosexual females showed a significant excess of sisters. Like previous studies of gender dysphoric youth and adults, these findings were consistent with the fraternal birth order effect. In addition, the greater frequency of only children and elevated numbers of older sisters among the homosexual female group adds to a small literature on sibship characteristics of potential relevance to the development of gender identity and sexual orientation in females.
BIRTH ORDER AND ANDROPHILIC MALE-TO-FEMALE TRANSSEXUALISM IN BRAZIL.
Vanderlaan, Doug P; Blanchard, Ray; Zucker, Kenneth J; Massuda, Raffael; Fontanari, Anna Martha Vaitses; Borba, André Oliveira; Costa, Angelo Bradelli; Schneider, Maiko Abel; Mueller, Andressa; Soll, Bianca Machado Borba; Schwarz, Karine; Da Silva, Dhiordan Cardoso; Lobato, Maria Inês Rodrigues
2016-11-07
Previous research has indicated that biological older brothers increase the odds of androphilia in males. This finding has been termed the fraternal birth order effect. The maternal immune hypothesis suggests that this effect reflects the progressive immunization of some mothers to male-specific antigens involved in fetal male brain masculinization. Exposure to these antigens, as a result of carrying earlier-born sons, is hypothesized to produce maternal immune responses towards later-born sons, thus leading to female-typical neural development of brain regions underlying sexual orientation. Because this hypothesis posits mechanisms that have the potential to be active in any situation where a mother gestates repeated male fetuses, a key prediction is that the fraternal birth order effect should be observable in diverse populations. The present study assessed the association between sexual orientation and birth order in androphilic male-to-female transsexuals in Brazil, a previously unexamined population. Male-to-female transsexuals who reported attraction to males were recruited from a specialty gender identity service in southern Brazil (n=118) and a comparison group of gynephilic non-transsexual men (n=143) was recruited at the same hospital. Logistic regression showed that the transsexual group had significantly more older brothers and other siblings. These effects were independent of one another and consistent with previous studies of birth order and male sexual orientation. The presence of the fraternal birth order effect in the present sample provides further evidence of the ubiquity of this effect and, therefore, lends support to the maternal immune hypothesis as an explanation of androphilic sexual orientation in some male-to-female transsexuals.
Birth order and communication skills of pharmacy students.
Murawski, M M; Miederhoff, P; Rule, W
1995-06-01
Pharmacy educators are training graduates in a concept of practice called pharmaceutical care. The movement towards patient care requires consideration of the personal and social qualities of trainees. All individuals attracted to pharmacy may not desire involvement in patient care. This preliminary study of pharmacy students of the relationships among birth order, empathy, and assertiveness behaviors using the Interpersonal Communication Inventory showed the incidence of firstborn students in this sample was not significantly higher than in the general population but the incidence of those born second was significantly lower. Regression analysis of individual items gave significant correlations between birth order and three items on the inventory. While few conclusions can be drawn, a clear direction for further research is indicated.
Sibship size, birth order, and personality among Kuwaiti college students.
Abdel-Khalek, Ahmed M; Lester, David
2007-08-01
In a sample of 460 (103 men, 357 women) Kuwaiti college students (M age=21.9 yr., SD=3.0), scores on the Arabic Scale of Optimism and Pessimism, the Death Obsession Scale, the Arabic Scale of Obsession-Compulsion, the Kuwait University Anxiety Scale, the Taoist Orientation Scale, and the Suicidal Ideation Scale were not associated with sibship size and birth order.
Park, Cheolsung; Chung, Wankyo
2012-01-01
We examine whether the effect of sibship size on education differs by the individual's birth order in low-income countries, using data from Matlab, Bangladesh. Exploiting exposure to the randomized family planning program in Matlab for identification, we find evidence that sibship size has negative effect on education and positive effect on labor force participation of the first and the second-born children, but no significant effect on education or labor force participation of the later-born...
Epilepsia e ordem de nascimento Epilepsy and birth order
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Paulo Cesar Sandler
1975-09-01
Full Text Available Mediante o método de Greenwood-Yule e o teste estatístico mais sensível de que se dispõe atualmente, o x² de Halperin, foi testada a possível associação entre a prevalência de epilepsia e a ordem de nascimento de 238 pacientes. Estes pacientes foram obtidos em dois hospitais de São Paulo, na tentativa de se controlar sua classe social; tratava-se de epilépticos com variados transtornos psiquiátricos. Concluiu-se por uma associação estatisticamente significante entre a doença e a ordem de nascimento dos 238 pacientes, com uma sobre-representação nos primeiros e nos últimos nascidos.This paper deals with birth order and epilepsy. The Greenwood-Yule's method was applied, with the most powerful statistical test available, Halperin's modified chi-square. The authors concluded that there is a consistent positive association between this illness prevalence and birth order of the patients, being first and last born over-represented, irrespective of their sibship size. The data were obtained in two psychiatric hospitals in the city of São Paulo, being social class factor qualitatively controlled. All the 238 patients studied suffered a wide range of psychiatric symptoms.
Kushnir, T.
1978-01-01
Reviews literature on birth order. An important conclusion is that birth order differences in anxiety level and affiliation are not generalized phenomena. Consistent birth order differences in both variables are found only among females. Firstborns are not habitually more anxious than laterborns and are not generally more affiliative than…
Blind adolescents' birth order as a determinant of their perception of family functioning dimensions
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Stanimirović Dragana
2013-01-01
Full Text Available While other theoreticians of personality stressed only the influence of parents in early childhood, Adler paid particular attention to a psychological position of a child among brothers/sisters. There is some empirical evidence that birth order may influence vocational choice, characteristic style of interacting with others, affiliation, anxiety, perception of parents' authority, and even intellectual capabilities. Visual impairment of a family member affects a family system and a sibling subsystem in a specific way. The goal of the research was to determine whether birth order influences perception of dimensions of family functioning in families with a blind adolescent and in families with an adolescent of typical development. The sample included 32 blind (experimental group and 32 subjects of typical development (control group aged 14 to 26, who lived in complete families with two or three children and without serious personal, marrital or family problems. The groups were paired by sex, age, professional status and birth order of adolescents, number of children in the family, type of family (nuclear; extended and environment (rural; urban. A Questionnaire of socio-demographic information and a Questionnaire of situation and family relationships RADIR by Knežević were applied for data collection. First-borns made lower appraisals of each dimension of family functioning than second-born respondents. There were no statistically significant differences in the control group. Differences in the experimental group were statistically significant in the following dimensions: Activity, Democracy and Structuring time and activity. Thus, the results show that first-born child's 'dethronement' has more effect if it is associated with blindness. This can be explained by fact that it is more difficult for a blind first-born child to catch up with a second-born 'rival'.
Review and theory of handedness, birth order, and homosexuality in men.
Blanchard, Ray
2008-01-01
Research has repeatedly shown that older brothers increase the odds of homosexuality in later-born males. This phenomenon has been called the fraternal birth order effect. The most highly developed explanation of this phenomenon is the maternal immune hypothesis, which proposes that the fraternal birth order effect reflects the progressive immunisation of some mothers to male-specific antigens by each succeeding male foetus and the concomitantly increasing effects of anti-male antibodies on the sexual differentiation of the brain in each succeeding male foetus. Recent studies indicate that older brothers increase the odds of homosexuality in right-handed males but not in non-right-handed males. The present article explores how the maternal immune hypothesis might be extended or modified to account for the apparent interaction of older brothers and handedness. Two possibilities are considered: (1) non-right-handed foetuses are insensitive to the presence of maternal anti-male antibodies, and (2) mothers of non-right-handed foetuses do not produce anti-male antibodies.
How Do Children Behave Regarding Their Birth Order in Dental Setting?
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Faezeh Ghaderi
2015-12-01
Full Text Available Statement of the Problem: Prediction of child cooperation level in dental setting is an important issue for a dentist to select the proper behavior management method. Many psychological studies have emphasized the effect of birth order on patient behavior and personality; however, only a few researches evaluated the effect of birth order on child’s behavior in dental setting. Purpose: This study was designed to evaluate the influence of children ordinal position on their behavior in dental setting. Materials and Method: A total of 158 children with at least one primary mandibular molar needing class I restoration were selected. Children were classified based on the ordinal position; first, middle, or last child as well as single child. A blinded examiner recorded the pain perception of children during injection based on Visual Analogue Scale (VAS and Sound, Eye and Movement (SEM scale. To assess the child's anxiety, the questionnaire known as “Dental Subscale of the Children's Fear Survey Schedule” (CFSS-DS was employed. Results: The results showed that single children were significantly less cooperative and more anxious than the other children (p<0.001. The middle children were significantly more cooperative in comparison with the other child's position (p< 0.001. Conclusion: Single child may behave less cooperatively in dental setting. The order of child birth must also be considered in prediction of child’s behavior for behavioral management.
The New Birth Order Book: Why You Are the Way You Are. Revised Edition.
Leman, Kevin
Based on the premise that birth order powerfully influences one's personality, one's marital partner, and one's parenting style, this book presents personal anecdotes, testimonials, and descriptions of well-known individuals or individuals seen in counseling to illustrate the impact of birth order. The book also presents practical ways to take…
Impact of Birth Order on Procrastination among College Students in Eldoret Town
Gabriel, Chege Kimani
2015-01-01
The study sought to investigate the impact of birth order on procrastination among college students in Eldoret town. The study sought to achieve the following objectives: (1) to find out the prevalence of procrastination among college students in Eldoret town, (2) to find out the relationship between birth order on procrastination among college…
Blanchard, Ray
2017-06-12
The fraternal birth order effect is the tendency for older brothers to increase the odds of homosexuality in later-born males. This study compared the strength of the effect in subjects from small versus large families and in homosexual subjects with masculine versus feminine gender identities. Meta-analyses were conducted on 30 homosexual and 30 heterosexual groups from 26 studies, totaling 7140 homosexual and 12,837 heterosexual males. The magnitude of the fraternal birth order effect was measured with a novel variable, the Older Brothers Odds Ratio, computed as (homosexuals' older brothers ÷ homosexuals' other siblings) ÷ (heterosexuals' older brothers ÷ heterosexuals' other siblings), where other siblings = older sisters + younger brothers + younger sisters. An Older Brothers Odds Ratio of 1.00 represents no effect of sexual orientation; values over 1.00 are positive evidence for the fraternal birth order effect. Evidence for the reliability of the effect was consistent. The Older Brothers Odds Ratio was significantly >1.00 in 20 instances, >1.00 although not significantly in nine instances, and nonsignificantly homosexual groups than in the other 18 homosexual groups. There was no evidence that the magnitude of the effect differs according to family size.
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Ochiai Hirotaka
2012-09-01
Full Text Available Abstract Background Although several studies have investigated the relationship between the number of siblings or birth order and childhood overweight, the results are inconsistent. In addition, little is known about the impact of having older or younger siblings on overweight among elementary schoolchildren. The present population-based study investigated the relationship of the number of siblings and birth order with childhood overweight and evaluated the impact of having younger or older siblings on childhood overweight among elementary schoolchildren in Japan. Methods Subjects comprised fourth-grade schoolchildren (age, 9–10 years in Ina Town during 1999–2009. Information about subjects’ sex, age, birth weight, birth order, number of siblings, lifestyle, and parents’ age, height, and weight was collected by a self-administered questionnaire, while measurements of subjects’ height and weight were done at school. Childhood overweight was defined according to age- and sex-specific cut-off points proposed by the International Obesity Task Force. A logistic regression model was used to calculate the odds ratio (OR and 95% confidence intervals (95% CI of "number of siblings" or "birth order" for overweight. Results Data from 4026 children were analyzed. Only children (OR: 2.13, 95% CI: 1.45-3.14 and youngest children (1.56, 1.13-2.16 significantly increased ORs for overweight compared with middle children. A larger number of siblings decreased the OR for overweight (P for trend P for trend Conclusions Being an only or youngest child was associated with childhood overweight, and having a larger number of younger siblings was negatively associated with overweight. The present study suggests that public health interventions to prevent childhood overweight need to focus on children from these family backgrounds.
Parish, T S
1990-01-01
In the present study, 334 youths evaluated their families by responding to the Personal Attribute Inventory for Children. An analysis of variance revealed no significant main effects due to respondents' birth order or gender, but did find a significant main effect due to family structure and a significant two-way interaction effect between respondents' family structure and gender. Specifically, males from divorced remarried families and females from divorced nonremarried families were found to evaluate their respective families significantly more negatively than did their counterparts from other familial configurations. Implications of these findings are discussed.
de Oliveira Meller, Fernanda; Assunção, M C F; Schäfer, A A; de Mola, C L; Barros, A J D; Dahly, D L; Barros, F C
2015-07-14
The aim of this study was to estimate the association between birth order and number of siblings with body composition in adolescents. Data are from a birth cohort study conducted in Pelotas, Brazil. At the age of 18 years, 4563 adolescents were located, of whom 4106 were interviewed (follow-up rate 81.3 %). Of these, 3974 had complete data and were thus included in our analysis. The variables used in the analysis were measured during the perinatal period, or at 11, 15 and/or 18 years of age. Body composition at 18 years was collected by air displacement plethysmography (BOD POD®). Crude and adjusted analyses of the association between birth order and number of siblings with body composition were performed using linear regression. All analyses were stratified by the adolescent sex. The means of BMI, fat mass index and fat-free mass index among adolescents were 23.4 (sd 4.5) kg/m², 6.1 (sd 3.9) kg/m² and 17.3 (sd 2.5) kg/m², respectively. In adjusted models, the total siblings remained inversely associated with fat mass index (β = - 0.37 z-scores, 95 % CI - 0.52, - 0.23) and BMI in boys (β = - 0.39 z-scores, 95 % CI - 0.55, - 0.22). Fat-free mass index was related to the total siblings in girls (β = 0.06 z-scores, 95 % CI - 0.04, 0.17). This research has found that number of total siblings, and not birth order, is related to the fat mass index, fat-free mass index and BMI in adolescents. It suggests the need for early prevention of obesity or fat mass accumulation in only children.
Birth order and recalled childhood gender nonconformity in Samoan men and fa'afafine.
Semenyna, Scott W; VanderLaan, Doug P; Vasey, Paul L
2017-04-01
Having a greater than average number of older biological brothers is a robust correlate of male androphilia (i.e., sexual attraction and arousal to adult males). Previous investigations have sought to understand whether this fraternal birth order (FBO) effect is also systematically related to recalled indicators of childhood gender nonconformity (CGN). However, these investigations have relied on data from low-fertility Western populations in which expressions of femininity in male children are routinely stigmatized and consequently, suppressed. The present study examined the FBO effect (among other sibship characteristics) and recalled indicators of CGN in Samoa, a high-fertility population, whose members are relatively tolerant of male femininity. Indeed, Samoans identify feminine androphilic males as belonging to an alternative gender category, known locally as fa'afafine. The present study compared the sibship characteristics of 231 fa'afafine and 231 opposite-sex attracted men from Samoa, as well as how these characteristics related to recalled CGN. Results replicated the well-established FBO effect for predicting male sexual orientation, with each older brother increasing the odds of being androphilic by 21%. However, no relationship was found between the number of older brothers (or other siblings) a participant had and their recalled CGN. Although fa'afafine reported significantly more CGN than Samoan men, CGN did not mediate the FBO effect, nor did the FBO effect and CGN interact to predict male sexual orientation. These findings are consistent with previous studies suggesting that the FBO effect is associated with male sexual orientation, but not childhood female-typical gender expression among androphilic males.
Personality, birth order and attachment styles as related to various types of jealousy
Buunk, Abraham (Bram)
1997-01-01
The relationships between jealousy, personality, attachment styles and birth order were examined in a sample of 100 Dutch men and 100 Dutch women. Three types of jealousy were examined: reactive jealousy (a negative response to the emotional or sexual involvement of the partner with someone else), p
Birth order and childhood type 1 diabetes risk: a pooled analysis of 31 observational studies
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Cardwell, Chris R; Stene, Lars C; Joner, Geir
2011-01-01
The incidence rates of childhood onset type 1 diabetes are almost universally increasing across the globe but the aetiology of the disease remains largely unknown. We investigated whether birth order is associated with the risk of childhood diabetes by performing a pooled analysis of previous...
Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age
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Yokoyama, Yoshie; Jelenkovic, Aline; Sund, Reijo
2016-01-01
We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years ...
Personality, birth order and attachment styles as related to various types of jealousy
Buunk, Abraham (Bram)
1997-01-01
The relationships between jealousy, personality, attachment styles and birth order were examined in a sample of 100 Dutch men and 100 Dutch women. Three types of jealousy were examined: reactive jealousy (a negative response to the emotional or sexual involvement of the partner with someone else),
Institute of Scientific and Technical Information of China (English)
邹国斌; 沙霞
2014-01-01
Objective To evaluate the associations between birth order,maternal abortion and mode of delivery and childhood acute leukemia risk.Method Multiple electronic databases were searched to identify relevant studies up to March 2013 using the search terms " childhood leukemia"," acute lymphoblastic leukemia"," acute myeloid leukemia"," birth order"," abortion "," miscarriage ","cesarean","birth characteristics" and "prenatal risk factor".Data from cohort and case-control studies were analyzed using the Stata software.Result Twenty-three studies were included in this meta-analysis according to the selection criteria.No significant associations were identified for birth order and mode of delivery (birth order =2:OR =0.97,95％ CI:0.89-1.05 ; birth order =3:OR =1.00,95％ CI:0.91-1.11 ; birth order ≥4:OR =1.02,95％ CI:0.87-1.20; mode of delivery:OR =1.05,95％ CI:0.96-1.15).However,there was a significant association between maternal abortion and childhood acute leukemia risk (spontaneous abortion:OR =1.21,95％ CI:1.05-1.41 ; induced abortion:OR =1.23,95％ CI:1.07-1.43).Furthermore,the stratified analysis by disease subtypes showed that spontaneous and induced abortions were significantly associated with the risks of childhood acute myeloid leukemia (OR =1.71,95％ CI:1.09-2.70) and acute lymphoblastic leukemia (OR =1.23,95％ CI:1.05-1.42),respectively.Conclusion This meta-analysis revealed that maternal abortion might contribute to the childhood acute leukemia risk.%目的 综合评价患儿出生顺序、孕妇流产史及分娩方式与儿童急性白血病发病风险之间的关系.方法 在PubMed、Google学术搜索、中国知网(CNKI)、万方数据库中以“childhoodleukemia"、“acute lymphoblastic leukemia"、“acute myeloid leukemia"、“birth order"、“abortion”、“miscarriage”、“caesarean”、“birth characteristics”、“prenatal risk factor”或其对应的中文词目为检索词,收集2013年3月前有关患儿出生顺序
Zambrana, Imac Maria; Ystrom, Eivind; Pons, Francisco
2012-02-01
To investigate the impact of child gender, maternal education, and birth order on language comprehension (LC) status at 18 and 36 months of age and on the change in LC between these time points. Gender interactions and interactions between maternal education and birth order are also examined. This study is based on data from the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health. Maternal report data on education, birth order, and child language in a sample of 44,921 children were used in linear regression analyses. At 18 and 36 months of age, first-born girls of mothers with high educational attainment had the highest level of LC. Between 18 and 36 months of age, first-born boys of mothers with high educational attainment had the highest increase in LC. Having a highly educated mother contributed more to the increase in LC in boys than in girls. The boys whose mothers had the highest education level had lower scores than the girls whose mothers had the lowest educational level, at both ages. Although significant, the considerable effect of high maternal education was not substantially dependent on birth-order status. Boys develop LC at a faster rate than girls between 18 and 36 months, but girls still remain superior in their level of LC at 36 months of age. Being firstborn or having a highly educated mother does not compensate for this lag.
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Robyn Donrovich
2014-11-01
Full Text Available Background: Family composition and household dynamics, both in early and in later life, influence individual health and longevity. Both positive and negative effects can be expected in terms of sibling size and composition. On one hand, siblings compete with each other, which may lead to resource dilution and increased adult mortality risks. On the other hand, siblings protect and care for each other, which may have a positive impact on longevity. Objective: To investigate the way in which sibling composition (with respect to sibship size, sex, and birth order in the family of orientation and the proximity of siblings in later life relates to adult mortality risks at ages 50+. Methods: Life courses of 258 men and 275 women from the Antwerp COR*-database were 'reconstructed' and analyzed by way of event history analysis using Gompertz shared frailty models. Results: Being higher in birth order related to significantly higher mortality risk after age 50 for men. Having older brothers, particularly those present in later life, was associated with very high excess mortality risk for both sexes, though men were more strongly disadvantaged. Having (more younger sisters present at RP (research person age 50 was related to significantly lower relative mortality risk for women. Conclusions: Our findings highlight the complex relationships between sibling and gender dynamics and mortality risk in later life. Evidence of a lasting impact of sibling competition on mortality risk over age 50 is found; and competition is only replaced by solidarity in critical times (e.g., widowhood, wherein older sibling presence dissimilarly impacts different social groups.
Shimakawa, Yusuke; Lemoine, Maud; Bottomley, Christian; Njai, Harr Freeya; Ndow, Gibril; Jatta, Abdoulie; Tamba, Saydiba; Bojang, Lamin; Taal, Makie; Nyan, Ousman; D'Alessandro, Umberto; Njie, Ramou; Thursz, Mark; Hall, Andrew J
2015-10-01
Early age at infection with Hepatitis B virus (HBV) increases the risk of chronic infection. Moreover, early HBV infection may further independently increase the risk of hepatocellular carcinoma (HCC) beyond its effect on chronicity. The distribution of birth order, a proxy for mode and timing of HBV transmission, was compared in The Gambia between hepatitis B surface antigen (HBsAg)-positive HCC cases recruited from hospitals (n = 72) and two HBsAg-positive control groups without HCC: population-based controls from a community HBV screening (n = 392) and hospital-based controls (n = 63). HCC risk decreased with increasing birth order in the population-based case-control analysis. Using first birth order as the reference, the odds ratios were 0.52 (95% CI: 0.20-1.36), 0.52 (0.17-1.56), 0.57 (0.16-2.05) and 0.14 (0.03-0.64) for second, third, fourth and greater than fourth birth order respectively (P = 0.01). A similar inverse association was observed in the hospital-based case-control comparison (P = 0.04). Compared to controls, HCC cases had earlier birth order, a proxy for young maternal age and maternal HBV viraemia at birth. This finding suggests that in chronic HBV carriers perinatal mother-to-infant transmission may increase HCC risk more than horizontal transmission. Providing HBV vaccine within 24 h of birth to interrupt perinatal transmission might reduce the incidence of HCC in The Gambia. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Blanchard, Ray
2014-07-01
The term "fraternal birth order effect" denotes a statistical relation most commonly expressed in one of two ways: Older brothers increase the odds of homosexuality in later born males or, alternatively, homosexual men tend to have more older brothers than do heterosexual men. The demonstrability of this effect depends partly on the adequate matching of the homosexual and heterosexual study groups with respect to mean family size. If the homosexual group has too many siblings, relative to the heterosexual group, the homosexual group will tend to show the expected excess of older brothers but may also show an excess of other sibling-types (most likely older sisters); if the homosexual group has too few siblings, it will tend not to show a difference in number of older brothers but instead may show a deficiency of other sibling-types (most likely younger brothers and younger sisters). In the first part of this article, these consequences are illustrated with deliberately mismatched groups selected from archived data sets. In the second part, two slightly different methods for transforming raw sibling data are presented. These are intended to produce family-size-corrected variables for each of the four original sibling parameters (older brothers, older sisters, younger brothers, and younger sisters). Both versions are shown to render the fraternal birth order effect observable in the deliberately mismatched groups. In the third part of the article, fraternal birth order studies published in the last 5 years were surveyed for failures to find a statistically significant excess of older brothers for the homosexual group. Two such studies were found in the nine examined. In both cases, the collective findings for older sisters, younger brothers, and younger sisters suggested that the mean family size of the homosexual groups was smaller than that of the heterosexual comparison groups. Furthermore, the individual findings for the four classes of siblings resembled those
Kulkarni, Abhishek; Ertekin, Deniz; Lee, Chi-Hon; Hummel, Thomas
2016-03-17
The precise recognition of appropriate synaptic partner neurons is a critical step during neural circuit assembly. However, little is known about the developmental context in which recognition specificity is important to establish synaptic contacts. We show that in the Drosophila visual system, sequential segregation of photoreceptor afferents, reflecting their birth order, lead to differential positioning of their growth cones in the early target region. By combining loss- and gain-of-function analyses we demonstrate that relative differences in the expression of the transcription factor Sequoia regulate R cell growth cone segregation. This initial growth cone positioning is consolidated via cell-adhesion molecule Capricious in R8 axons. Further, we show that the initial growth cone positioning determines synaptic layer selection through proximity-based axon-target interactions. Taken together, we demonstrate that birth order dependent pre-patterning of afferent growth cones is an essential pre-requisite for the identification of synaptic partner neurons during visual map formation in Drosophila.
METABOLIC AND BEHAVIORAL PARAMETERS IN NEWBORN PIGLETS IN RELATION TO BIRTH ORDER
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H. SĂRĂNDAN
2013-12-01
Full Text Available The experiment had 2 phases:During the first phase 19 sows were monitored during farrowing; the piglets were numbered according to birth order, they were weighed and there were recorded the time each piglet was born and when it first suckled. There was calculated the time from the beginning of the farrowing until the time each piglet was born (TNPP and the time from birth until the first suckle (TPS. A statistical correlation was established between these parameters.During the second experimental phase, for 49 piglets from 5 sows were determined: birth weight, TPS, glycemia at birth (G0 and after the first suckle (G1, rectal temperature at birth (T0 and after the first suckles (T1. This data was statistically analyzed using the Mann-Whitney U test.Respecting the birth order, TPS is shorter for piglets born last (p<0.05. Average TPS was 23.04±2.49 minutes; during this time glycemia rises from 58.35 mg% to 64.35 mg% and rectal temperature drops from 38.58°C to 37.35°C. T0 is positively correlated with G0 (p<0.01 with G1 (p<0.01 and T1 (p<0.01. G0 is highly correlated to G1 (r=0.8855; p=0.
Birth order and childhood type 1 diabetes risk: a pooled analysis of 31 observational studies
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Cardwell, Chris R; Stene, Lars C; Joner, Geir
2010-01-01
BACKGROUND: The incidence rates of childhood onset type 1 diabetes are almost universally increasing across the globe but the aetiology of the disease remains largely unknown. We investigated whether birth order is associated with the risk of childhood diabetes by performing a pooled analysis...... and after adjustment for confounders, and investigate heterogeneity. RESULTS: Data were available for 6 cohort and 25 case-control studies, including 11¿955 cases of type 1 diabetes. Overall, there was no evidence of an association prior to adjustment for confounders. After adjustment for maternal age...... at birth and other confounders, a reduction in the risk of diabetes in second- or later born children became apparent [fully adjusted OR¿=¿0.90 95% confidence interval (CI) 0.83-0.98; P¿=¿0.02] but this association varied markedly between studies (I(2)¿=¿67%). An a priori subgroup analysis showed...
Relation of birth order and scores on measures of pathological narcissism.
Curtis, J M; Cowell, D R
1993-02-01
To study the relationship between birth order and pathological narcissism, it was predicted that firstborn and only children would score significantly higher on standardized measures of pathological narcissism. Two such measures, the Millon Clinical Multiaxial Inventory and the Narcissistic Personality Inventory, were administered to 50 randomly selected subjects from a metropolitan mental health and family treatment agency. Subjects were asked to indicate their ordinal birth positions, e.g., first, middle, last, or only, and then were administered both instruments. Analysis supported the initial prediction by indicating that firstborn and only children had higher mean scores on the measures of pathological narcissism. It might be advisable for clinicians to identify patients' ordinal positions while appraising relevant diagnostic criteria and eventual treatment planning.
Csermely, Gyula; Czeizel, Andrew E; Veszprémi, Béla
2015-02-01
Multiple congenital abnormalities are caused by chromosomal aberrations, mutant major genes and teratogens. A minor proportion of these patients are identified as syndromes but the major part belonging to the group of unclassified multiple CAs (UMCAs). The main objective of this study was to evaluate the maternal age and birth order in pregnant women who had offspring affected with UMCA. The strong association between numerical chromosomal aberrations, e.g., Down syndrome and advanced maternal age is well-known and tested here. The Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980 to 1996, yielded a large population-based national data set with 22,843 malformed newborns or fetuses ("informative cases") included 1349 UMCA cases with their 2407 matched controls. Case-control comparison of maternal age and birth order was made for cases with UMCA, stratified by component numbers and their controls. In addition, 834 cases with Down syndrome were compared to 1432 matched controls. The well-known advanced maternal age with the higher risk for Down syndrome was confirmed. The findings of the study suggest that the young age of mothers associates with the higher risk of UMCA, in addition birth order 4 or more associates with the higher risk for UMCA with 2 and 3 component CAs. This study was the first to analyze the possible maternal and birth order effect for cases with UMCA, and the young age and higher birth order associated with a higher risk for UMCA. © 2014 Wiley Periodicals, Inc.
山西省食管癌患者出生顺序研究%Study on the birth order of patients with esophagus cancer in Shanxi province
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韩斐; 范亚峰; 王国平; 丁悌; 李建民; 苏文; 高泽锋; 韩小友
2012-01-01
Objective To explore the relationship between esophagus cancer patients and both environmental and genetic factors,through analyzing the data on birth orders from esophagus cancer patients of Shanxi province.Methods Both Greenwood and Haldane methods on birth order were used to study the 1101 cases with esophagus cancer from Shanxi province.All the patients had received surgery and were diagnosed,by pathological evidence.First certificates of the patients were confirmed through the standard genetic epidemiologic investigation.Birth order was investigated on probands of the 1101 cases with esophagus cancer and their 44 siblings.Results Results form the Greenwood method showed that there was a tendency for cases with esophagus cancer in birth orders First to Third.However,the Haldane method showed that the results were quite different between actual value and the average theory value of 6A (6A(actual value)=17 118,(X)6A(average theory value) =19 290,X=∣6A-(X)6A∣/√V6A =7.63,X ＞ 2) which suggested that the birth order had some effects on the occurrence of esophagus cancer.In addition,the actual value of 6A was lower than the theoretic average value,and the parents at younger productive age or baby at the first birth was easy to develop esophagus cancer.Conclusion Esophagus cancer was related with the birth order,especially at early order,which was not consistent with the national reports on esophagus cancer.Results from this study suggested that there were certain effects of environmental risk factors on esophagus cancer patients.%目的 分析山西省食管癌患者的出生顺序,探讨环境因素、遗传因素与食管癌的关系.方法 采用Greenwood和Haldane的出生顺序方法,以山西省肿瘤医院1101例住院食管癌手术患者为先证者进行遗传流行病学调查,并对1101例先证者及44例食管癌患病同胞进行出生顺序研究.结果 Greenwood法分析结果显示,食管癌患者较多发生在出生顺序1～3
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Ahmad Ghanizadeh
2012-09-01
Full Text Available Objective: It is not clear whether sibling’s gender ratio is associated with attention deficit hyperactivity disorder (ADHD. This study examines whether inattentiveness severity and hyperactivity/impulsivity severity are associated with birth order of children with ADHD.Method: Participants are a clinical sample of 173 children and adolescents with ADHD and 43 ones without ADHD. Diagnoses were made using Diagnostic and Statistical Manual of Mental Disorders forth edition-Text Revision (DSM-IV-TR, diagnostic criteria according to face-to-face interview with the children and their parents. ADHD DSM-IV checklist was used to measure inattentiveness and hyperactivity/impulsivity scores.Results: The association of birth order and diagnosis of ADHD was not statistically significant after adjusting for covariate factors. The gender ratio of siblings is not associated with ADHD.Conclusion: Birth order and siblings gender ratio are independent of ADHD diagnosis. The results of this study support the fact that genetic factors rather than environmental factor of birth order is associated with ADHD. Moreover, contrary to autism, the current results do not suggest the androgen theory for ADHD.
Pollet, Thomas V.; Dijkstra, Pieternel; Barelds, Dick P. H.; Buunk, Abraham P.
2010-01-01
The present study set out to examine the relationship between birth order and the dominance facet of extraversion in a community sample of around 1500 participants. In contrast, to Sulloway's (1995) predictions, the present study, using a between-family design, found firstborns to be less extraverte
Oshima-Takane, Yuriko; And Others
1996-01-01
Compared language development of 16 firstborn and 16 secondborn children at 21 months to investigate whether secondborn children benefit from overheard conversations between caregivers and older siblings. Found that secondborn children were more advanced that firstborn in pronoun production, while not differing general language development,…
Karamanolaki, Hara; Spyropoulou, Areti C; Iliadou, Aggeliki; Vousoura, Eleni; Vondikaki, Stamatia; Pantazis, Nikos; Vaslamatzis, Grigoris
2016-01-01
The purpose of this study was to assess the possible effect of recalled traumatic experiences, perceived parental rearing styles, and family parameters on the occurrence of borderline personality disorder (BPD) versus other personality disorders (other-PDs). A total of 88 adult outpatients with personality disorders completed the Traumatic Antecedents Questionnaire and the Egna Minnen av Barndoms Uppfostran, which measures perceptions regarding parental rearing. Results indicated that incidence of traumatic childhood experiences was higher among those in the BPD group compared to those in the other-PD group. Firstborns were less likely to carry a diagnosis of BPD over other-PDs. Also, significantly more BPD compared to other-PD patients reported being the father's favorite child over siblings. Results suggest that traumatic experiences, birth order, and family interactions in the presence of siblings seem to differentially affect the formation of borderline diagnosis compared to other-PDs. Limitations and clinical implications of the study are discussed in detail.
Van Jaarsveld, Lizelle
2012-01-01
The aim of this study is to explore and describe children’s experiences of the repositioning of their psychological birth order in a reconstituted family. The aim of this study is also to contribute to a better understanding of this phenomenon to aid the parents of these children as well as professionals working with such families. The systems theory was used as the meta-theory of this study. Gestalt field theory formed the connection between the systems theory and Adlerian theory, to port...
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Steven Hawken
Full Text Available OBJECTIVE: We investigated the association between a child's birth order and emergency room (ER visits and hospital admissions following 2-,4-,6- and 12-month pediatric vaccinations. METHODS: We included all children born in Ontario between April 1(st, 2006 and March 31(st, 2009 who received a qualifying vaccination. We identified vaccinations, ER visits and admissions using health administrative data housed at the Institute for Clinical Evaluative Sciences. We used the self-controlled case series design to compare the relative incidence (RI of events among 1(st-born and later-born children using relative incidence ratios (RIR. RESULTS: For the 2-month vaccination, the RIR for 1(st-borns versus later-born children was 1.37 (95% CI: 1.19-1.57, which translates to 112 additional events/100,000 vaccinated. For the 4-month vaccination, the RIR for 1(st-borns vs. later-borns was 1.70 (95% CI: 1.45-1.99, representing 157 additional events/100,000 vaccinated. At 6 months, the RIR for 1(st vs. later-borns was 1.27 (95% CI: 1.09-1.48, or 77 excess events/100,000 vaccinated. At the 12-month vaccination, the RIR was 1.11 (95% CI: 1.02-1.21, or 249 excess events/100,000 vaccinated. CONCLUSIONS: Birth order is associated with increased incidence of ER visits and hospitalizations following vaccination in infancy. 1(st-born children had significantly higher relative incidence of events compared to later-born children.
New birth weight reference standards customised to birth order and sex of babies from South India
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Kumar Velusamy Saravana
2013-02-01
Full Text Available Abstract Background The foetal growth standards for Indian children which are available today suffer due to methodological problems. These are, for example, not adhering to the WHO recommendation to base gestational age on the number of completed weeks and secondly, not excluding mothers with risk factors. This study has addressed both the above issues and in addition provides birthweight reference ranges with regard to sex of the baby and maternal parity. Methods Data from the labour room register from 1996 to 2010 was obtained. A rotational sampling scheme was used i.e. the 12 months of the year were divided into 4 quadrants. All deliveries in January were considered to represent the first quadrant. Similarly all deliveries in April, July and October were considered to represent 2nd, 3rd and 4th quadrants. In each successive year different months were included in each quadrant. Only those mothers aged 20–39 years and delivered between 24 to 42 weeks gestational age were considered. Those mothers with obstetric risk factors were excluded. The reference standards were fitted using the Generalized Additive Models for Location Scale and Shape (GAMLSS method for Box – Cox t distribution with cubic spline smoothing. Results There were 41,055 deliveries considered. When women with risk factors were excluded 19,501 deliveries could be included in the final analysis. The male babies of term firstborn were found to be 45 g heavier than female babies. The mean birthweights were 2934 g and 2889.5 g respectively. Similarly, among the preterm babies, the first born male babies weighed 152 g more than the female babies. The mean birthweights were 1996 g and 1844 g respectively. In the case of later born babies, the term male babies weighed 116grams more than the females. The mean birth weights were 3085 grams and 2969 grams respectively. When considering later born preterm babies, the males outweighed the female babies by 111 grams. The
Macdonald, A. P.
1971-01-01
It was found that (a) later borns from two-child families were more external than those from larger families; (b) later borns were more external than only children or firstborns; (c) only children and firstborns were more socially responsible than later borns; and (d) firstborns were more rigid than only-child and later-born Ss. (Author)
Beaulieu, A D; Aalhus, J L; Williams, N H; Patience, J F
2010-08-01
The objective of this study was to investigate the relationships among birth weight, birth order, or litter size on growth performance, carcass quality, and eating quality of the ultimate pork product. Data were collected from 98 pig litters and, with the addition of recording birth weight and birth order, farrowing and piglet management were according to normal barn practices. In the nursery and during growout, the pigs received the normal feeding program for the barn and, with the addition of individual tattooing, were marketed as per standard procedure. From 24 litters, selected because they had at least 12 pigs born alive and represented a range of birth weights, 4 piglets were chosen (for a total of 96 piglets) and sent to Agriculture and Agri-Food Canada-Lacombe Research Centre (Lacombe, Alberta, Canada) when they reached 120 kg for extensive meat quality and sensory analysis. Individual BW was measured at birth, on the day of weaning, 5 wk after weaning, at nursery exit, at first pull, and at the time of marketing. Litter sizes were divided into 3 categories: small (3 to 10 piglets), medium (11 to 13 piglets), and large (14 to 19 piglets). There were 4 birth-weight quartiles: 0.80 to 1.20, 1.25 to 1.45, 1.50 to 1.70, and 1.75 to 2.50 kg. Increased litter size resulted in reduced mean birth weight (P 0.05) when slaughtered at the same endpoint. Lighter birth-weight pigs had reduced BW at weaning, 5 and 7 wk postweaning, and at first pull and had increased days to market (P 0.05). In conclusion, increased litter size resulted in decreased mean birth weight but no change in days to market. Lighter birth-weight pigs took longer to reach market. Despite some differences in histological properties, birth weight had limited effects on carcass composition or final eating quality of the pork when slaughtered at the same BW and large litter size resulted in more pigs weaned and marketed compared with the smaller litters. We concluded that based on the conditions of
Birth order and risk taking in athletics: a meta-analysis and study of major league baseball.
Sulloway, Frank J; Zweigenhaft, Richard L
2010-11-01
According to expectations derived from evolutionary theory, younger siblings are more likely than older siblings to participate in high-risk activities. The authors test this hypothesis by conducting a meta-analysis of 24 previous studies involving birth order and participation in dangerous sports. The odds of laterborns engaging in such activities were 1.48 times greater than for firstborns (N = 8,340). The authors also analyze performance data on 700 brothers who played major league baseball. Consistent with their greater expected propensity for risk taking, younger brothers were 10.6 times more likely to attempt the high-risk activity of base stealing and 3.2 times more likely to steal bases successfully (odds ratios). In addition, younger brothers were significantly superior to older brothers in overall batting success, including two measures associated with risk taking. As expected, significant heterogeneity among various performance measures for major league baseball players indicated that older and younger brothers excelled in different aspects of the game.
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Preeti Tabitha Louis
2016-01-01
Full Text Available Background: Perfectionism is a multifaceted concept. It had both advantages and disadvantages. Perfectionistic traits have been associated with leadership and very intellectual people. The present study is an attempt to understand if engineering students possess perfectionistic orientation and whether it influences self-efficacy, social connectedness, and achievement motivation. Materials and Methods: The present study adopts a random sampling design to evaluate the presence of perfectionism as a personality trait among undergraduate engineering students (N = 320. Standardized inventories such as Almost Perfect Scale-Revised were administered first to identify perfectionists and second to differentiate the adaptive from the maladaptive perfectionists. Scheduled interviews were conducted with students to obtain information regarding birth order and family functioning. Results: Findings from the study reveal that there were a significant number of maladaptive perfectionists and that they experienced higher levels of personal and societal demands leading to a negative emotional well-being in comparison to the adaptive perfectionists. We also observed that first-born children were more likely to display a perfectionistic self-presentation and from scheduled interviews, we understood that paternal influences were stronger when it came to decision-making and display of conscientiousness. Conclusion: The study draws on important implications for helping students to understand perfectionism and to respond to demands of the family and societal subsystems in a positive and an adaptive manner.
Yule, Morag A; Brotto, Lori A; Gorzalka, Boris B
2014-02-01
Human asexuality is defined as a lack of sexual attraction to anyone or anything and it has been suggested that it may be best conceptualized as a sexual orientation. Non-right-handedness, fraternal birth order, and finger length ratio (2D:4D) are early neurodevelopmental markers associated with sexual orientation. We conducted an Internet study investigating the relationship between self-identification as asexual, handedness, number of older siblings, and self-measured finger-lengths in comparison to individuals of other sexual orientation groups. A total of 325 asexuals (60 men and 265 women; M age, 24.8 years), 690 heterosexuals (190 men and 500 women; M age, 23.5 years), and 268 non-heterosexuals (homosexual and bisexual; 64 men and 204 women; M age, 29.0 years) completed online questionnaires. Asexual men and women were 2.4 and 2.5 times, respectively, more likely to be non-right-handed than their heterosexual counterparts and there were significant differences between sexual orientation groups in number of older brothers and older sisters, and this depended on handedness. Asexual and non-heterosexual men were more likely to be later-born than heterosexual men, and asexual women were more likely to be earlier-born than non-heterosexual women. We found no significant differences between sexual orientation groups on measurements of 2D:4D ratio. This is one of the first studies to test and provide preliminary empirical support for an underlying neurodevelopmental basis to account for the lack of sexual attraction characteristic of asexuality.
大学生出生次序、自尊与人际关系%The Birth Order,Self -esteem and Interpersonal Relationship of College Students
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韩晓红
2015-01-01
This paper aims to explore the differences between the birth order and relationships in considering the self -esteem acts as a personality factor.We have chosen 300 students in Zhengzhou University to investigate by using the self -esteem scale and interpersonal relationships assessment scale.The results show that there are not obvious differences in self -esteem in dif-ferent birth orders,including the differences between only one or non -only -child student.The extent of troubled relation-ships and its communication and interpersonal relationship factors between only one or non -only -child student is not signifi-cant,but it is significant between the students in different birth orders.%目的：结合自尊这一人格因素探讨不同出生次序的大学生人际关系之间的差异。方法：采用自尊量表、人际关系综合诊断量表对郑州大学300名大学生进行测查。结果：独生与非独生、非独生子女中不同出生次序的大学生自尊水平差异不显著。独生与非独生子女之间的人际交往困扰总分及各因子分之间差异不显著，在非独生子女中，不同出生次序大学生在与人交谈困扰因子、人际交往困扰因子及人际关系困扰总分上差异显著。
Barks, P M; Laird, R A
2016-04-01
Classic theories on the evolution of senescence make the simplifying assumption that all offspring are of equal quality, so that demographic senescence only manifests through declining rates of survival or fecundity. However, there is now evidence that, in addition to declining rates of survival and fecundity, many organisms are subject to age-related declines in the quality of offspring produced (i.e. parental age effects). Recent modelling approaches allow for the incorporation of parental age effects into classic demographic analyses, assuming that such effects are limited to a single generation. Does this 'single-generation' assumption hold? To find out, we conducted a laboratory study with the aquatic plant Lemna minor, a species for which parental age effects have been demonstrated previously. We compared the size and fitness of 423 laboratory-cultured plants (asexually derived ramets) representing various birth orders, and ancestral 'birth-order genealogies'. We found that offspring size and fitness both declined with increasing 'immediate' birth order (i.e. birth order with respect to the immediate parent), but only offspring size was affected by ancestral birth order. Thus, the assumption that parental age effects on offspring fitness are limited to a single generation does in fact hold for L. minor. This result will guide theorists aiming to refine and generalize modelling approaches that incorporate parental age effects into evolutionary theory on senescence.
DEFF Research Database (Denmark)
Kragh, Marie; Larsen, Jeppe Madura; Thysen, Anna Hammerich
2016-01-01
the association between birth-order and the functional response of stimulated cord blood T cells. Method: Purified cord blood T cells were polyclonally activated with anti-CD3/CD28-coated beads in a subgroup of 28 children enrolled in the COPSAC2010 birth cohort. Expression levels of seven activation markers...... on helper and cytotoxic T cells as well as the percentage of CD4+CD25+ T cells were assessed by flow cytometry. Production of IFN-γ, TNF-α, IL-17, IL-4, IL-5, IL-13 and IL-10 was measured in supernatants. Results: IL-10 secretion (P = 0.007) and CD25 expression on CD4+ helper T cells (P = 0.......0003) in activated cord blood T cells were selectively reduced in first-born children, while the percentage of CD4+CD25+ cord blood T cells was independent of birth-order. Conclusion: First-born infants display a reduced anti-inflammatory profile in T cells at birth. This possible in utero ‘birth-order’ T cell...
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Izabela Tissot Antunes Sampaio
2010-01-01
Full Text Available Este estudo avaliou o gênero e a ordem de nascimento como variáveis moderadoras das práticas educativas parentais e da percepção da preferência parental a partir do ponto de vista dos filhos. Participaram da pesquisa 322 adolescentes entre 13 e 17 anos. Foram utilizados dois instrumentos para a coleta de dados: Inventário de Estilos Parentais (IEP e um questionário desenvolvido pelos autores. Os dados foram analisados através da estatística não-paramétrica (Mann-Whitney e Kruskal-Wallis. Através da análise dos resultados, constatou-se que: (a o gênero dos filhos interfere significativamente nos índices de estilo parental; (b as primogênitas apresentaram significativamente maior risco de sofrer com as práticas parentais negativas e (c a percepção da preferência parental é influenciada pelo gênero e ordem de nascimento dos filhos.This study aimed at assessing gender and birth order influence on parenting and perceived parental favoritism from the children perspective. The participants were 322 adolescents aged between 13 and 17 years old. Two instruments were used to collect data - Parenting Styles Inventory and a questionnaire developed by the authors. Non-parametrical statistics (Mann-Whitney and Kruskal-Wallis were used to analyze the obtained data. Results have shown that: (a child gender has significant influence on the score of parenting styles; (b firstborn girls present significantly higher risk of suffering negative parental practices and, (c the perceived parental favoritism is significantly modulated by both gender and birth order.
Ratings of self and parents by youth: are they affected by family status, gender, and birth order?
Parish, T S
1991-01-01
In the present study, 648 youths from across the state of Kansas voluntarily evaluated themselves and their parents using the Personal Attribute Inventory for Children. Self-concept was found to be significantly higher for those from intact families in comparison with those from divorced remarried families. Evaluations of mothers were significantly higher for those from intact and divorced nonremarried families as compared with those from divorced remarried families. The ratings of fathers by youths from intact families were significantly more favorable than the ratings by those from either divorced nonremarried or divorced remarried families. Interestingly, gender by family status two-way interaction effects were also found for self-concept and ratings of fathers. Possible explanations for these findings, and their implications, are discussed.
1987-02-17
Testament and the works of William Shakespeare are replete with examples showing that the ordinal position of an individual in his or her family was of...presented him with the coat-of-many-colors. Of the tragic Shakespearean figures of Macbeth and his wife, both were firstborns and saw life as only a
Institute of Scientific and Technical Information of China (English)
周律; 陈功; 徐铭蔚; 王佳
2012-01-01
在美国等西方国家,代际时间转移动机是公共转移项目和政策的关键决定因素。然而,在中国文化中,这一概念相对比较新颖。目前尚无子女的孩次、性别与中国农村老年人代际时间转移之间影响的研究。本文旨在从农村地区父母的角度,按子女的性别和孩次,探究时间转移的动机。本研究的数据为2009年从中国安徽省巢湖地区收集。研究结果显示从父母的视角分析,子女的孩次对代际时间转移动机有显著的影响,而子女性别的影响不显著。此外,本文讨论了对政府政策和未来研究的启示。%In the United States and other Western countries, the intergenerational transfer motivation is a key determinant of public transfer programs and policies. However, in Chinese culture, the concept is relatively new. Currently there is less research about rural birth order and gender influence on intergenerational time transfer in China. This article analyzed intergenerational time transfer motivation by the birth order and gender in perspective of rural parents. In this study, the data collected from Chaohu, Anhui Province, China in 2009. The results showed that from the perspective of parents, their children＇s birth order have a significant impact on intergenerational transfer motivation and children＇s gender had no significant effect. In addition, the article discusses the revelation of government policy and future research.
DULIEGE, AM; AMOS, CI; FELTON, S; BIGGAR, RJ; ZIEGLER, J; CRUIKSHANK, M; LEVY, J; MEATES, MA; GIBB, D; MAYAUX, MJ; TEGLAS, JP; LAURENT, C; BLANCHE, S; ROUZIOUX, C; HELLINGGIESE, G; MATTNER, U; HOEGER, PH; CONLON, T; GRIFFIN, E; DEMARIA, A; BENEDETTO, A; PRINCIPI, N; GIAQUINTO, C; GIANCOMELLI, A; MOK, J; CASABONA, J; FORTUNY, C; URIZ, S; PEREZ, JM; TUSETRUIZ, MC; LEON, P; ELORZA, JFY; CANOSA, C; BRANDLE, B; SEGER, R; NADAL, D; IRION, O; WYLER, CA; DAVIS, P; LALLEMANT, M; LALLEMANTLECOEUR, S; HITIMANA, DG; LEPAGE, P; VANDEPERRE, P; DABIS, F; MARUM, L; NDUGWA, C; TINDYEBWA, D; ACENG, E; MMIRO, F; SUTONGAS, T; OLNESS, K; LAPOINTE, N; RUBINSTEIN, A; BURGE, D; STECHENBERG, BW; COOPER, E; REGAN, AM; SHIPKOWITZ, S; WIZNIA, A; BRUNELL, PA; COURVILLE, T; RUTSTEIN, R; MCINTOSH, K; PETRU, A; OLEARY, M; CHURCH, J; TAYLOR, S; SQUIRES, J; MALLORY, M; YOGEV, R; RAKUSAN, T; PLUMLEY, S; SHELTON, MM; WILFERT, C; LANE, B; ABRAMS, EJ; RANA, S; CHANDAVASU, O; PUVABANDITSIN, S; CHOW, JH; SHAH, K; NACHMAN, S; ONEILL, R; SELWYN, P; SHOENBAUM, E; BARZILAI, A; WARFORD, R; AHERN, L; PAHWA, S; PNUGOTI, N; GARCIATRIAS, DE; BAKSHI, S; LANDESMAN, S; MENDEZ, H; MOROSO, G; MENDEZBAUTISTA, RD; FIKRIG, S; BELMAN, A; KLINE, MW; HANSON, C; EDELSON, P; HINDS, G; VANDYKE, R; CLARK, R; WARA, DW; MANIO, EB; JOHNSON, G; WELLS, L; JOHNSON, JP; ALGER, L; LUZURIAGA, K; MASTRUCCI, T; SUNKUTU, MR; RODRIGUEZ, Z; DOYLE, M; REUBEN, J; BRYSON, Y; DILLON, M; SIMPSON, BJ; ANDIMAN, W; URIBE, P; Klauke, B.
1995-01-01
Background: We evaluated data from prospectively identified twins to understand better the mechanisms and covariates of mother-to-infant transmission of human immunodeficiency virus (HIV). Methods: Using data obtained from an international collaboration and multivariate quasilikelihood modeling, we
Robyn Donrovich; Paul Puschmann; Koen Matthijs
2014-01-01
Background: Family composition and household dynamics, both in early and in later life, influence individual health and longevity. Both positive and negative effects can be expected in terms of sibling size and composition. On one hand, siblings compete with each other, which may lead to resource dilution and increased adult mortality risks. On the other hand, siblings protect and care for each other, which may have a positive impact on longevity. Objective: To investigate the way in which...
Institute of Scientific and Technical Information of China (English)
黄艳苹; 李玲
2011-01-01
Objective: Students of birth order on personality and mental health status. Methods: This study examined 11,183 students in a university in Guangzhou in the birth order of their personality characteristics and mental health. Conclusion: in terms of personality. the most outgoing child, second son of the second, the eldest son of the most introverted (F＝9.215,P＜0.01) ; on the neuroticism factor, most vulnerable to anxiety and tension eldest son, second son of the second, the most stable one-child emotional(F＝3.194, P＜0.05); the second, the most stable one-child emotional; the second son of the highest cover, that is most vulnerable to the impact of social desirability, and child to cover the lowest (F＝7.545,P＜0.01).ln mental health, the highest level of child mental health, the eldest son, second son and youngest son among the mental health there were no significant differences (F＝7.575 , P＜0.05) .%目的:了解出生顺序对大学生人格及心理健康的影响状况.方法:调查广州某高校11183名大学生的出生顺序,分析其对人格特征和心理健康的影响.结果:在人格特征方面,独生子女最为外向;长子最为内向(F=9.215,P<0.01),次子次之;在神经质因子上,长子最易焦虑与紧张,次子次之,独生子女情绪最稳定(F=3.194,P<0.05);次子的掩饰性最高,即最容易受社会赞许性的影响,而独生子女掩饰性最低(F=7.545,P<0.01);在心理健康方面,独生子女的心理健康水平最高,长子、次子和幼子的心理健康3者之间没有显著性差异(F=7.575,P<0.05).
Ecotoxicological effects extrapolation models
Energy Technology Data Exchange (ETDEWEB)
Suter, G.W. II
1996-09-01
One of the central problems of ecological risk assessment is modeling the relationship between test endpoints (numerical summaries of the results of toxicity tests) and assessment endpoints (formal expressions of the properties of the environment that are to be protected). For example, one may wish to estimate the reduction in species richness of fishes in a stream reach exposed to an effluent and have only a fathead minnow 96 hr LC50 as an effects metric. The problem is to extrapolate from what is known (the fathead minnow LC50) to what matters to the decision maker, the loss of fish species. Models used for this purpose may be termed Effects Extrapolation Models (EEMs) or Activity-Activity Relationships (AARs), by analogy to Structure-Activity Relationships (SARs). These models have been previously reviewed in Ch. 7 and 9 of and by an OECD workshop. This paper updates those reviews and attempts to further clarify the issues involved in the development and use of EEMs. Although there is some overlap, this paper does not repeat those reviews and the reader is referred to the previous reviews for a more complete historical perspective, and for treatment of additional extrapolation issues.
Modeling and Simulating Environmental Effects
Guest, Peter S.; Murphree, Tom; Frederickson, Paul A.; Guest, Arlene A.
2012-01-01
MOVES Research & Education Systems Seminar: Presentation; Session 4: Collaborative NWDC/NPS M&S Research; Moderator: Curtis Blais; Modeling and Simulating Environmental Effects; speakers: Peter Guest, Paul Frederickson & Tom Murphree Environmental Effects Group
Institute of Scientific and Technical Information of China (English)
计德永; 王君
2015-01-01
目的：探讨活产儿出生顺序与早产及低出生体质量的关系,为提高人口出生质量提供参考。方法选取2013年在某市妇幼保健院分娩的所有单胎活产儿为研究对象,资料收集于新生儿出生医学信息登记系统。结果活产儿出生顺序在1~8之间(1．4±0．6),出生顺序为1占65．9%(4055/6151),出生顺序为2占29．8%(1835/6151),出生顺序为3及以上占4．2%(261/6151)。出生顺序为1、2、3及以上的活产儿的早产检出率分别为8．2%、14．1%和27．2%(趋势χ2=113．620, P<0．05),低出生体质量检出率分别为6．2%、11．1%和26．8%(趋势χ2=132．228, P<0．05)。控制产妇年龄、文化程度及户口所在地后多因素分析显示,出生顺序为2、3及以上的活产儿出现早产的危险性分别是出生顺序1的1．546倍和3．186倍,出现低出生体质量的危险性分别是出生顺序1的1．991倍和5．530倍。结论高出生顺序为早产及低出生体质量发生的高危因素。%Objective To explore the relationship between birth order and premature, low birth weight among live neonates in order to provide the basis for improving birth quality. Methods All live neonates of single birth were selected from this hospital in 2013, and the data were collected from Medical Birth Register. Results The number of birth order was 1~8 (1. 4 ± 0. 6), the proportion of first birth or-der was 65. 9% (4 055/6 151), second birth order was 29. 8% (1 835/6 151), and third or more birth order was 4. 2% (261/6 151). The prevalence rate of premature birth was 8. 2% in first birth order, 14. 1% in second birth and 27. 2% in third or more birth (χ2 =113. 620, P<0. 05), and the prevalence rate of low birth weight was 6. 2 in first birth order, 11. 1% in second birth and 26. 8% in third or more birth (χ2 =132. 228, P<0. 05). The factors of maternal age, educational level and residence were controlled and multivariate analysis showed that, the risk of premature
Segal, Nancy L
2008-02-01
A brief overview of Sulloway's (1996) theory of birth order and personality is presented. A reared apart twin approach for testing his personality findings regarding openness to experience and conscientiousness in first borns and later borns is described. This is followed by summaries of three recent twin studies. The topics include cancer risk in mother of twins, sexual dysfunction in males and responder behavior during ultimatum games. This article concludes with a discussion of twinning rates and rituals among the Yoruba of western Nigeria, and descriptions of two unusual reunions between siblings and twins.
Kriging with mixed effects models
Directory of Open Access Journals (Sweden)
Alessio Pollice
2007-10-01
Full Text Available In this paper the effectiveness of the use of mixed effects models for estimation and prediction purposes in spatial statistics for continuous data is reviewed in the classical and Bayesian frameworks. A case study on agricultural data is also provided.
Size Effect in Continuum Modeling
Energy Technology Data Exchange (ETDEWEB)
Lu, Wei-Yang [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Foulk, James W. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Huestis, Edwin M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Connelly, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Song, Bo [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Yang, Nancy Y. C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engineered Materials
2008-09-01
The mechanical properties of some materials (Cu, Ni, Ag, etc.) have been shown to develop strong dependence on the geometric dimensions, resulting in a size effect. Several theories have been proposed to model size effects, but have been based on very few experiments conducted at appropriate scales. Some experimental results implied that size effects are caused by increasing strain gradients and have been used to confirm many strain gradient theories. On the other hand, some recent experiments show that a size effect exists in the absence of strain gradients. This report describes a brief analytical and experimental study trying to clarify the material and experimental issues surrounding the most influential size-effect experiments by Fleck et al (1994). This effort is to understand size effects intended to further develop predictive models.
Mixed Effects Models for Complex Data
Wu, Lang
2009-01-01
Presenting effective approaches to address missing data, measurement errors, censoring, and outliers in longitudinal data, this book covers linear, nonlinear, generalized linear, nonparametric, and semiparametric mixed effects models. It links each mixed effects model with the corresponding class of regression model for cross-sectional data and discusses computational strategies for likelihood estimations of mixed effects models. The author briefly describes generalized estimating equations methods and Bayesian mixed effects models and explains how to implement standard models using R and S-Pl
Toy models for wrapping effects
Penedones, João; Vieira, Pedro
2008-08-01
The anomalous dimensions of local single trace gauge invariant operators in Script N = 4 supersymmetric Yang-Mills theory can be computed by diagonalizing a long range integrable Hamiltonian by means of a perturbative asymptotic Bethe ansatz. This formalism breaks down when the number of fields of the composite operator is smaller than the range of the Hamiltonian which coincides with the order in perturbation theory at study. We analyze two spin chain toy models which might shed some light on the physics behind these wrapping effects. One of them, the Hubbard model, is known to be closely related to Script N = 4 SYM. In this example, we find that the knowledge of the effective spin chain description is insufficient to reconstruct the finite size effects of the underlying electron theory. We compute the wrapping corrections for generic states and relate them to a Luscher like approach. The second toy models are long range integrable Hamiltonians built from the standard algebraic Bethe ansatz formalism. This construction is valid for any symmetry group. In particular, for non-compact groups it exhibits an interesting relation between wrapping interactions and transcendentality.
Better models are more effectively connected models
Nunes, João Pedro; Bielders, Charles; Darboux, Frederic; Fiener, Peter; Finger, David; Turnbull-Lloyd, Laura; Wainwright, John
2016-04-01
The concept of hydrologic and geomorphologic connectivity describes the processes and pathways which link sources (e.g. rainfall, snow and ice melt, springs, eroded areas and barren lands) to accumulation areas (e.g. foot slopes, streams, aquifers, reservoirs), and the spatial variations thereof. There are many examples of hydrological and sediment connectivity on a watershed scale; in consequence, a process-based understanding of connectivity is crucial to help managers understand their systems and adopt adequate measures for flood prevention, pollution mitigation and soil protection, among others. Modelling is often used as a tool to understand and predict fluxes within a catchment by complementing observations with model results. Catchment models should therefore be able to reproduce the linkages, and thus the connectivity of water and sediment fluxes within the systems under simulation. In modelling, a high level of spatial and temporal detail is desirable to ensure taking into account a maximum number of components, which then enables connectivity to emerge from the simulated structures and functions. However, computational constraints and, in many cases, lack of data prevent the representation of all relevant processes and spatial/temporal variability in most models. In most cases, therefore, the level of detail selected for modelling is too coarse to represent the system in a way in which connectivity can emerge; a problem which can be circumvented by representing fine-scale structures and processes within coarser scale models using a variety of approaches. This poster focuses on the results of ongoing discussions on modelling connectivity held during several workshops within COST Action Connecteur. It assesses the current state of the art of incorporating the concept of connectivity in hydrological and sediment models, as well as the attitudes of modellers towards this issue. The discussion will focus on the different approaches through which connectivity
Mechanical effects in cookoff modeling
Energy Technology Data Exchange (ETDEWEB)
Gross, R.J.; Baer, M.R.; Hobbs, M.L.
1994-07-01
Complete cookoff modeling of energetic material in confined geometries must couple thermal, chemical and mechanical effects. In the past, modeling has focused on the prediction of the onset of combustion behavior based only on thermal-chemistry effects with little or no regard to the mechanical behavior of the energetic material. In this paper, an analysis tool is outlined which couples thermal, chemical, and mechanical behavior for one-dimensional Geometries comprised of multi-materials. A reactive heat flow code, XCHEM, and a quasistatic mechanics code, SANTOS, have been completely coupled using, a reactive, elastic-plastic constitutive model describing pressurization of the energetic material. This new Thermally Reactive Elastic-plastic explosive code, TREX, was developed to assess the coupling, of mechanics with thermal chemistry making multidimensional cookoff analysis possible. In this study, TREX is applied to confined and unconfined systems. The confined systems simulate One-Dimensional Time to explosion (ODTX) experiments in both spherical and cylindrical configurations. The spherical ODTX system is a 1.27 cm diameter sphere of TATB confined by aluminum exposed to a constant external temperature. The cylindrical ODTX system is an aluminum tube filled with HMX, NC, and inert exposed to a constant temperature bath. Finally. an unconfined system consisting of a hollow steel cylinder filled with a propellant composed of Al, RMX, and NC, representative of a rocket motor, is considered. This model system is subjected to transient internal and external radiative/convective boundary conditions representative of 5 minutes exposure to a fire. The confined systems show significant pressure prior to ignition, and the unconfined system shows extrusion of the propellent suggesting that the energetic material becomes more shock sensitive.
Birth Order, Gender and Affiliation in Various Situations.
Fox, Shaul
1981-01-01
Administered two questionnaires to 800 Israeli subjects which examine the affiliation need in four groups of situations. No differences were found between first and later-borns in their tendency to associate with others. Results showed significant interaction between sex and specific situational factors. (Author/RC)
Twin birth order, birthweight and birthweight discordance: any relationship
Directory of Open Access Journals (Sweden)
Onyiriuka A.N.
2010-12-01
Full Text Available Background: It is widely believed that in twin pairs, at birth, the first-born weigh more than the second-born but this concept has been challenged. Objective: To assess the truthfulness of this common concept that first-born twins are usually heavier than their second-born siblings at birth. Methods: In a series of 104 sets of live-born twins, the birth weights of first-born twins were compared with those of their second-born siblings, after controlling for gender. Their intra-pair birthweight differences were determined and twin pairs whose birthweight difference was 15% or more were designated as discordant. Results: Twin I was heavier than Twin II in 61.5% of cases while Twin II was heavier than Twin I in 28.9% of cases. Twins I and II had equal birthweights in 9.6% of cases. Comparing the mean birthweight of the first-born-male twin with that of second-born- male twin, it was 2515+427g (95% Confidence Interval, CI=2402-2628 versus 2432 +435g (95% CI=2321-2543 p>0.05. The mean birthweight of first-born-female twin was 2326+445g (95% CI=2214-2439 while that of the second-born-female twin was 2325+501g (95% CI=2197-2453 p>0.05. When the birthweight difference exceeded 750g, the probability that Twin I will be heavier than Twin II was 83.3% (5 of 6. Conclusion: Although the first-born twin was more often heavier than their second-born siblings, either could weigh more or less at birth. The larger the birthweight difference between growth-discordant twin pair, the greater the probability that the heavier twin would be delivered first
221 THE ROLE OF BIRTH ORDER IN SUBSTANCE RELATED ...
African Journals Online (AJOL)
Administrator
Journal of Language, Technology & Entrepreneurship in Africa, Vol.2. No.2 2010 ... discovery in the social science field (Hartshorne, Salem-Hartshorne & Hartshorne, 2009). Research in this ..... Retrieved on 25/07/2010 from Science Direct ...
Random Effect and Latent Variable Model Selection
Dunson, David B
2008-01-01
Presents various methods for accommodating model uncertainty in random effects and latent variable models. This book focuses on frequentist likelihood ratio and score tests for zero variance components. It also focuses on Bayesian methods for random effects selection in linear mixed effects and generalized linear mixed models
A Departmental Cost-Effectiveness Model.
Holleman, Thomas, Jr.
In establishing a departmental cost-effectiveness model, the traditional cost-effectiveness model was discussed and equipped with a distant and deflation equation for both benefits and costs. Next, the economics of costing was examined and program costing procedures developed. Then, the model construct was described as it was structured around the…
The differential susceptibility to media effects model
Valkenburg, P.M.; Peter, J.
2013-01-01
In this theoretical article, we introduce the Differential Susceptibility to Media Effects Model (DSMM), a new, integrative model to improve our understanding of media effects. The DSMM organizes, integrates, and extends the insights developed in earlier microlevel media-effects theories. It
The differential susceptibility to media effects model
Valkenburg, P.M.; Peter, J.
2013-01-01
In this theoretical article, we introduce the Differential Susceptibility to Media Effects Model (DSMM), a new, integrative model to improve our understanding of media effects. The DSMM organizes, integrates, and extends the insights developed in earlier microlevel media-effects theories. It disting
The differential susceptibility to media effects model
Valkenburg, P.M.; Peter, J.
2013-01-01
In this theoretical article, we introduce the Differential Susceptibility to Media Effects Model (DSMM), a new, integrative model to improve our understanding of media effects. The DSMM organizes, integrates, and extends the insights developed in earlier microlevel media-effects theories. It disting
An Effective ARMA Modeling Method.
1981-04-01
directed towards spectral analysis, power spectral density function the preponderance of effort has been directed to- wards two special cases of the...domain spectral density function than from pole model, and, the general ARMA model is seen to its equivalent time domain autocorrelation sequence. be...n-k) (11) prediction. Assuming this prediction behavior, it k-I then follows from relationship (11) that the spectral density function of the time
Modeling the effects of labeling
DEFF Research Database (Denmark)
Juhl, Hans Jørn; Fjord, Thomas Ahle; Poulsen, Carsten Stig
A new approach to evaluate the consequences of labeling is presented and applied to test the potential effect of a label on fresh fish. Labeling effects on quality perceptions and overall quality are studied. The empirical study is based on an experimental design and nearly 500 respondents...
Modeling of Pressure Effects in HVDC Cables
DEFF Research Database (Denmark)
Szabo, Peter; Hassager, Ole; Strøbech, Esben
1999-01-01
A model is developed for the prediction of pressure effects in HVDC mass impregnatedcables as a result of temperature changes.To test the model assumptions, experiments were performed in cable like geometries.It is concluded that the model may predict the formation of gas cavities....
A Model for Measuring Puffery Effects.
Vanden Bergh, Bruce G.; Reid, Leonard N.
The purpose of this paper is to describe and discuss a conceptual model for experimentally investigating the effects of advertising puffery. The various sections contain a discussion of puffery as a legal concept, a description and discussion of the proposed model, research support for the model, and implications for future research on puffery.…
Analytical modelling of temperature effects on synapses
Kufel, Dominik S
2016-01-01
It was previously reported, that temperature may significantly influence neural dynamics on different levels of brain modelling. Due to this fact, while creating the model in computational neuroscience we would like to make it scalable for wide-range of various brain temperatures. However currently, because of a lack of experimental data and an absence of analytical model describing temperature influence on synapses, it is not possible to include temperature effects on multi-neuron modelling level. In this paper, we propose first step to deal with this problem: new analytical model of AMPA-type synaptic conductance, which is able to include temperature effects in low-frequency stimulations. It was constructed on basis of Markov model description of AMPA receptor kinetics and few simplifications motivated both experimentally and from Monte Carlo simulation of synaptic transmission. The model may be used for efficient and accurate implementation of temperature effects on AMPA receptor conductance in large scale...
How Programming Can Make a Difference for Gifted Students--A Multi-Methods Model.
Hall, Eleanor G.
A multimethod model of educating gifted and talented students was based on graduate students' study of 14 eminent self actualized individuals. Common environmental elements of these individuals were found in parent background, birth order, relationship with family, education, task commitment, personality traits, and interests. The model was…
Modelling of Size Effect with Regularised Continua
Directory of Open Access Journals (Sweden)
H. Askes
2004-01-01
Full Text Available A nonlocal damage continuum and a viscoplastic damage continuum are used to model size effects. Three-point bending specimens are analysed, whereby a distinction is made between unnotched specimens, specimens with a constant notch and specimens with a proportionally scaled notch. Numerical finite element simulations have been performed for specimen sizes in a range of 1:64. Size effects are established in terms of nominal strength and compared to existing size effect models from the literature.
Little Higgs model effects in →
Indian Academy of Sciences (India)
S Rai Choudhury; Ashok Goyal; A S Cornell; Naveen Gaur
2007-11-01
Though the predictions of the standard model (SM) are in excellent agreement with experiments, there are still several theoretical problems associated with the Higgs sector of the SM, where it is widely believed that some new physics will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we have investigated the effects of the LH model on → scattering [1].
Instructional Models Effective in Distance Education.
Jackman, Diane H.; Swan, Michael K.
The purpose of this study was to identify which instructional models based on the framework of Joyce, Weil, and Showers, could be used effectively in distance education over the Interactive Video Network (IVN) system in North Dakota. Instructional models have been organized into families such as Information Processing, Social, Personal, and…
Modelling of Deterioration Effects on Concrete Structures
Directory of Open Access Journals (Sweden)
B. Teplý
2002-01-01
Full Text Available In order to predict the service life of concrete structures models for deterioration effects are needed. This paper has the form of a survey, listing and describing such analytical models, namely carbonation of concrete, ingress of chlorides, corrosion of reinforcing steel and prestressing tendons. The probabilistic approach is applied.
Modelling synergistic effects of appetite regulating hormones
DEFF Research Database (Denmark)
Schmidt, Julie Berg; Ritz, Christian
2016-01-01
We briefly reviewed one definition of dose addition, which is applicable within the framework of generalized linear models. We established how this definition of dose addition corresponds to effect addition in case only two doses per compound are considered for evaluating synergistic effects. The....... The link between definitions was exemplified for an appetite study where two appetite hormones were studied....
A Test of the Combined Effects Model.
Kimsey, William D.; And Others
Two waves of telephone interviews with a sample of 141 voters were used in a study of political communication effects during the 1974 congressional election in the Illinois 24th Congressional District. Seven variables specified by the combined-effects model were derived from the interviews and factor analyzed. Two factors were found and…
Optical Hall effect-model description: tutorial.
Schubert, Mathias; Kühne, Philipp; Darakchieva, Vanya; Hofmann, Tino
2016-08-01
The optical Hall effect is a physical phenomenon that describes the occurrence of magnetic-field-induced dielectric displacement at optical wavelengths, transverse and longitudinal to the incident electric field, and analogous to the static electrical Hall effect. The electrical Hall effect and certain cases of the optical Hall effect observations can be explained by extensions of the classic Drude model for the transport of electrons in metals. The optical Hall effect is most useful for characterization of electrical properties in semiconductors. Among many advantages, while the optical Hall effect dispenses with the need of electrical contacts, electrical material properties such as effective mass and mobility parameters, including their anisotropy as well as carrier type and density, can be determined from the optical Hall effect. Measurement of the optical Hall effect can be performed within the concept of generalized ellipsometry at an oblique angle of incidence. In this paper, we review and discuss physical model equations, which can be used to calculate the optical Hall effect in single- and multiple-layered structures of semiconductor materials. We define the optical Hall effect dielectric function tensor, demonstrate diagonalization approaches, and show requirements for the optical Hall effect tensor from energy conservation. We discuss both continuum and quantum approaches, and we provide a brief description of the generalized ellipsometry concept, the Mueller matrix calculus, and a 4×4 matrix algebra to calculate data accessible by experiment. In a follow-up paper, we will discuss strategies and approaches for experimental data acquisition and analysis.
A periodic pricing model considering reference effect
Directory of Open Access Journals (Sweden)
Yang Hui
2016-01-01
Full Text Available The purpose of this paper is to investigate the optimal pricing strategies with reference effects in revenue management settings. We firstly propose a static pricing model with the properties of stochastic demand, finite horizon and fixed capacity, and prove the existence and uniqueness of the solution. Secondly, we extend the fixed pricing model to a periodic pricing model and incorporate a memory-based reference price in the demand function to investigate how the reference effect impacts on traditional revenue management decisions. We present numerical examples in both low demand situations and high demand situations for different levels of reference effects and different updating frequencies. The results show that the dynamic pricing strategies are superior to a static one even when reference effects are taken into consideration. We also provide some manage-rial insights including pricing directions, pricing dispersion and the optimal updating frequency for both demand situations.
Dynamical effects of overparametrization in nonlinear models
Aguirre, Luis Antonio; Billings, S. A.
1995-01-01
This paper is concemed with dynamical reconstruction for nonlinear systems. The effects of the driving function and of the complexity of a given representation on the bifurcation patter are investigated. It is shown that the use of different driving functions to excite the system may yield models with different bifurcation patterns. The complexity of the reconstructions considered is quantified by the embedding dimension and the number of estimated parameters. In this respect it appears that models which reproduce the original bifurcation behaviour are of limited complexity and that excessively complex models tend to induce ghost bifurcations and spurious dynamical regimes. Moreover, some results suggest that the effects of overparametrization on the global dynamical behaviour of a nonlinear model may be more deleterious than the presence of moderate noise levels. In order to precisely quantify the complexity of the reconstructions, global polynomials are used although the results are believed to apply to a much wider class of representations including neural networks.
Modelling Nuclear Effects in Neutrino Scattering
Leitner, T; Mosel, U
2006-01-01
We have developed a model to describe the interactions of neutrinos with nucleons and nuclei via charged and neutral currents, focusing on the region of the quasielastic and Delta(1232) peaks. For neutrino nucleon collisions a fully relativistic formalism is used. The extension to finite nuclei has been done in the framework of a coupled-channel BUU transport model where we have studied exclusive channels taking into account in-medium effects and final state interactions.
Modeling socioeconomic status effects on language development.
Thomas, Michael S C; Forrester, Neil A; Ronald, Angelica
2013-12-01
Socioeconomic status (SES) is an important environmental predictor of language and cognitive development, but the causal pathways by which it operates are unclear. We used a computational model of development to explore the adequacy of manipulations of environmental information to simulate SES effects in English past-tense acquisition, in a data set provided by Bishop (2005). To our knowledge, this is the first application of computational models of development to SES. The simulations addressed 3 new challenges: (a) to combine models of development and individual differences in a single framework, (b) to expand modeling to the population level, and (c) to implement both environmental and genetic/intrinsic sources of individual differences. The model succeeded in capturing the qualitative patterns of regularity effects in both population performance and the predictive power of SES that were observed in the empirical data. The model suggested that the empirical data are best captured by relatively wider variation in learning abilities and relatively narrow variation in (and good quality of) environmental information. There were shortcomings in the model's quantitative fit, which are discussed. The model made several novel predictions, with respect to the influence of SES on delay versus giftedness, the change of SES effects over development, and the influence of SES on children of different ability levels (gene-environment interactions). The first of these predictions was that SES should reliably predict gifted performance in children but not delayed performance, and the prediction was supported by the Bishop data set. Finally, the model demonstrated limits on the inferences that can be drawn about developmental mechanisms on the basis of data from individual differences. PsycINFO Database Record (c) 2013 APA, all rights reserved.
Dynamic hysteresis modeling including skin effect using diffusion equation model
Hamada, Souad; Louai, Fatima Zohra; Nait-Said, Nasreddine; Benabou, Abdelkader
2016-07-01
An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.
Dynamic hysteresis modeling including skin effect using diffusion equation model
Energy Technology Data Exchange (ETDEWEB)
Hamada, Souad, E-mail: souadhamada@yahoo.fr [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Louai, Fatima Zohra, E-mail: fz_louai@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Nait-Said, Nasreddine, E-mail: n_naitsaid@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Benabou, Abdelkader, E-mail: Abdelkader.Benabou@univ-lille1.fr [L2EP, Université de Lille1, 59655 Villeneuve d’Ascq (France)
2016-07-15
An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.
Event models and the fan effect.
Radvansky, G A; O'Rear, Andrea E; Fisher, Jerry S
2017-08-01
The current study explored the persistence of event model organizations and how this influences the experience of interference during retrieval. People in this study memorized lists of sentences about objects in locations, such as "The potted palm is in the hotel." Previous work has shown that such information can either be stored in separate event models, thereby producing retrieval interference, or integrated into common event models, thereby eliminating retrieval interference. Unlike prior studies, the current work explored the impact of forgetting up to 2 weeks later on this pattern of performance. We explored three possible outcomes across the various retention intervals. First, consistent with research showing that longer delays reduce proactive and retroactive interference, any retrieval interference effects of competing event models could be reduced over time. Second, the binding of information into events models may weaken over time, causing interference effects to emerge when they had previously been absent. Third, and finally, the organization of information into event models could remain stable over long periods of time. The results reported here are most consistent with the last outcome. While there were some minor variations across the various retention intervals, the basic pattern of event model organization remained preserved over the two-week retention period.
Mesomechanical modeling of shape memory effect
Vokoun, David; Kafka, Vratislav
1999-06-01
Shape memory alloys (SMA) are well known materials. There is a lot of technical applications making use of their unique properties. Most of the significant applications are based on use of the thermomechancial properties. Growing number of those applications causes a need for an universal mathematical model with ability to describe all thermomechancial properties of SMA by relatively simple final set of constitutive equations that could be helpful for development of further sophisticated shape memory applications. Unfortunately, a lot of attention has been paid to metallurgical research of shape memory alloys in a few last decades and less attention was dedicated to shape memory modeling. Our model does not claim to be a universal model, but only one contribution to modeling of shape memory effect for binary SMA. The model is adapted for the most applied SMA -- nitinol and is based on the hypothesis that in the course of shape memory effect the distances of first atomic neighbors (Ni-Ti) remain nearly unchanged, whereas the distances of second neighbors (Ti-Ti and Ni-Ni) change substantially. Consequently, we consider some mechanical properties of Ni-substructure and Ti- substructure separately. The mechanical behavior of Ti- substructure is modeled as elastic whereas that of Ni- substructure as elasto-plastic. The resulting relatively simple differential constitutive equations express relationship among internal stress tensors, macroscopic stress tensors, macroscopic strain tensors and temperature.
Modeling of the magnetic Barkhausen effect
Clatterbuck, D. M.; Garcia, V. J.; Johnson, M. J.; Jiles, D. C.
2000-05-01
The magnetic Barkhausen effect has been found particularly useful for the nondestructive evaluation of ferromagnetic alloys. It has been shown to be sensitive to both the microstructure and the stress state of a material. In order to improve interpretation of the Barkhausen signals, models are needed which are able to directly relate the Barkhausen signals to material properties such as grain size. In this paper, the advantages and disadvantages of two existing magnetic Barkhausen models are studied with a view to their suitability for use in the field of nondestructive evaluation. The model of Alessandro, Beatrice, Bertotti, and Montorsi describes the pinning field which interacts with a domain wall in terms of a Wiener-Levy stochastic process. The domain wall velocity is then assumed to depend linearly on the difference between the local magnetic field and this pinning field. The assumptions of this model limit its use to experiments where the permeability and rate-of-change of applied field are constant. The model of Jiles, Sipahi, and Williams assumes that the Barkhausen activity in a given time interval is proportional to the rate-of-change of the magnetization which can be calculated from the hysteresis model of Jiles and Atherton. The model uses Poisson statistics to describe the stochastic nature of the Barkhausen events. A new model which incorporates ideas from both of these older models is introduced. The new model allows for changes in permeability with applied field and can accurately reproduce the frequency response of experimental Barkhausen signals. In order to validate the model, experiments were performed by measuring the magnetic flux produced when a sample was magnetized in a solenoid. The high-frequency components of the flux signal represent Barkhausen events and were separated from the main signal using a high-pass filter. This approach allowed quantitative comparisons to be made between the experiments and the model.—This work was
Modelling vocal anatomy's significant effect on speech
de Boer, B.
2010-01-01
This paper investigates the effect of larynx position on the articulatory abilities of a humanlike vocal tract. Previous work has investigated models that were built to resemble the anatomy of existing species or fossil ancestors. This has led to conflicting conclusions about the relation between
Anomalous effective lagrangians and vector resonance models
Pallante, E.; Petronzio, R.
1993-01-01
Chiral lagrangians including vector resonances have been shown to saturate the finite part of some of the counterterms needed to regularize ordinary one-loop effective lagrangians of pseudoscalar interactions with external currents. The equivalence between different models has been discussed in the
Random effect selection in generalised linear models
DEFF Research Database (Denmark)
Denwood, Matt; Houe, Hans; Forkman, Björn;
We analysed abattoir recordings of meat inspection codes with possible relevance to onfarm animal welfare in cattle. Random effects logistic regression models were used to describe individual-level data obtained from 461,406 cattle slaughtered in Denmark. Our results demonstrate that the largest...
Effective models for excitons in carbon nanotubes
DEFF Research Database (Denmark)
Cornean, Horia; Duclos, Pierre; Ricaud, Benjamin
We analyse the low lying spectrum of a model of excitons in carbon nanotubes. Consider two particles with a Coulomb self-interaction, placed on an infinitely long cylinder. If the cylinder radius becomes small, the low lying spectrum is well described by a one-dimensional effective Hamiltonian...
The effects of family structure on the educational attainment of siblings in Hungary
Eijck, K. van; Graaf, P.M. de
1995-01-01
In this article we examine the impact of family structure on educational attainment in Hungary. Using a data-set collected in 1983 with information on all siblings of 17146 primary respondents, the effects of family size, birth order, and spacing were investigated. Hypotheses on these effects were b
Projecting Policy Effects with Statistical Models Projecting Policy Effects with Statistical Models
Directory of Open Access Journals (Sweden)
Christopher Sims
1988-03-01
Full Text Available This paper attempts to briefly discus the current frontiers in quantitative modeling for forecastina and policy analvsis. It does so by summarizing some recent developmenrs in three areas: reduced form forecasting models; theoretical models including elements of stochastic optimization; and identification. In the process, the paper tries to provide some remarks on the direction we seem to be headed. Projecting Policy Effects with Statistical Models
Radiative Effects in the Standard Model Extension
Zhukovskii, V C; Murchikova, E M
2006-01-01
The possibility of radiative effects induced by the Lorentz and CPT non-invariant interaction term for fermions in the Standard Model Extension is investigated. In particular, electron-positron photo-production and photon emission by electrons and positrons were studied. The rates of these processes were calculated in the Furry picture. It was demonstrated that the rates obtained in the framework of the model adopted strongly depend on the polarization states of the particles involved. Indeed, ultra-relativistic particles should occupy states with a preferred spin orientation, i.e., photons have the sign of polarization opposite to the sign of the effective potential, while charged particle are preferably in the state with the helicity coinciding with the sign of the effective potential. This leads to evident spatial asymmetries which may have certain consequences observable in astrophysical and cosmological studies.
Multiphysics Modelling of the Mandel- Cryer Effect
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E Holzbecher
2016-03-01
Full Text Available In porous medium studies the Mandel-Cryer effect is known, describing non-monotonic pore-water pressure evolution in response to loading or to changed stress conditions. In a 2D poro-elastic model we couple the pore water hydraulics with mechanics (HM. The Mandel-Cryer effect is identified in parts of the model region that are far from the drainage boundary. At parts of the loaded boundary an even more complex pressure evolution is revealed. Variations of the Biot-parameter as the coupling parameter clearly indicate the relevance of the two-way coupling between the involved physical regimes. Hence the Mandel-Cryer effect is a typical result of multi-physical coupling.
Biologically based multistage modeling of radiation effects
Energy Technology Data Exchange (ETDEWEB)
William Hazelton; Suresh Moolgavkar; E. Georg Luebeck
2005-08-30
This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of
Effective orthorhombic anisotropic models for wavefield extrapolation
Ibanez-Jacome, W.
2014-07-18
Wavefield extrapolation in orthorhombic anisotropic media incorporates complicated but realistic models to reproduce wave propagation phenomena in the Earth\\'s subsurface. Compared with the representations used for simpler symmetries, such as transversely isotropic or isotropic, orthorhombic models require an extended and more elaborated formulation that also involves more expensive computational processes. The acoustic assumption yields more efficient description of the orthorhombic wave equation that also provides a simplified representation for the orthorhombic dispersion relation. However, such representation is hampered by the sixth-order nature of the acoustic wave equation, as it also encompasses the contribution of shear waves. To reduce the computational cost of wavefield extrapolation in such media, we generate effective isotropic inhomogeneous models that are capable of reproducing the firstarrival kinematic aspects of the orthorhombic wavefield. First, in order to compute traveltimes in vertical orthorhombic media, we develop a stable, efficient and accurate algorithm based on the fast marching method. The derived orthorhombic acoustic dispersion relation, unlike the isotropic or transversely isotropic ones, is represented by a sixth order polynomial equation with the fastest solution corresponding to outgoing P waves in acoustic media. The effective velocity models are then computed by evaluating the traveltime gradients of the orthorhombic traveltime solution, and using them to explicitly evaluate the corresponding inhomogeneous isotropic velocity field. The inverted effective velocity fields are source dependent and produce equivalent first-arrival kinematic descriptions of wave propagation in orthorhombic media. We extrapolate wavefields in these isotropic effective velocity models using the more efficient isotropic operator, and the results compare well, especially kinematically, with those obtained from the more expensive anisotropic extrapolator.
Hysteresis modeling in graphene field effect transistors
Energy Technology Data Exchange (ETDEWEB)
Winters, M.; Rorsman, N. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412-96 Göteborg (Sweden); Sveinbjörnsson, E. Ö. [Science Institute, University of Iceland, IS-107 Reykjavik (Iceland)
2015-02-21
Graphene field effect transistors with an Al{sub 2}O{sub 3} gate dielectric are fabricated on H-intercalated bilayer graphene grown on semi-insulating 4H-SiC by chemical vapour deposition. DC measurements of the gate voltage v{sub g} versus the drain current i{sub d} reveal a severe hysteresis of clockwise orientation. A capacitive model is used to derive the relationship between the applied gate voltage and the Fermi energy. The electron transport equations are then used to calculate the drain current for a given applied gate voltage. The hysteresis in measured data is then modeled via a modified Preisach kernel.
SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS
Directory of Open Access Journals (Sweden)
Vasilica Magdalena SOMEŞFĂLEAN
2014-06-01
Full Text Available Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed other models that are the main subject of this research, which explains how and why persuasive communication works, to understand why some approaches are effective and others are not.
Effect on Prediction when Modeling Covariates in Bayesian Nonparametric Models.
Cruz-Marcelo, Alejandro; Rosner, Gary L; Müller, Peter; Stewart, Clinton F
2013-04-01
In biomedical research, it is often of interest to characterize biologic processes giving rise to observations and to make predictions of future observations. Bayesian nonparametric methods provide a means for carrying out Bayesian inference making as few assumptions about restrictive parametric models as possible. There are several proposals in the literature for extending Bayesian nonparametric models to include dependence on covariates. Limited attention, however, has been directed to the following two aspects. In this article, we examine the effect on fitting and predictive performance of incorporating covariates in a class of Bayesian nonparametric models by one of two primary ways: either in the weights or in the locations of a discrete random probability measure. We show that different strategies for incorporating continuous covariates in Bayesian nonparametric models can result in big differences when used for prediction, even though they lead to otherwise similar posterior inferences. When one needs the predictive density, as in optimal design, and this density is a mixture, it is better to make the weights depend on the covariates. We demonstrate these points via a simulated data example and in an application in which one wants to determine the optimal dose of an anticancer drug used in pediatric oncology.
Modelling of rate effects at multiple scales
DEFF Research Database (Denmark)
Pedersen, R.R.; Simone, A.; Sluys, L. J.
2008-01-01
At the macro- and meso-scales a rate dependent constitutive model is used in which visco-elasticity is coupled to visco-plasticity and damage. A viscous length scale effect is introduced to control the size of the fracture process zone. By comparison of the widths of the fracture process zone......, the length scale in the meso-model and the macro-model can be coupled. In this fashion, a bridging of length scales can be established. A computational analysis of a Split Hopkinson bar test at medium and high impact load is carried out at macro-scale and meso-scale including information from the micro-scale....
Estimation in Dirichlet random effects models
Kyung, Minjung; Casella, George; 10.1214/09-AOS731
2010-01-01
We develop a new Gibbs sampler for a linear mixed model with a Dirichlet process random effect term, which is easily extended to a generalized linear mixed model with a probit link function. Our Gibbs sampler exploits the properties of the multinomial and Dirichlet distributions, and is shown to be an improvement, in terms of operator norm and efficiency, over other commonly used MCMC algorithms. We also investigate methods for the estimation of the precision parameter of the Dirichlet process, finding that maximum likelihood may not be desirable, but a posterior mode is a reasonable approach. Examples are given to show how these models perform on real data. Our results complement both the theoretical basis of the Dirichlet process nonparametric prior and the computational work that has been done to date.
Entanglement effects in model polymer networks
Everaers, R.; Kremer, K.
The influence of topological constraints on the local dynamics in cross-linked polymer melts and their contribution to the elastic properties of rubber elastic systems are a long standing problem in statistical mechanics. Polymer networks with diamond lattice connectivity (Everaers and Kremer 1995, Everaers and Kremer 1996a) are idealized model systems which isolate the effect of topology conservation from other sources of quenched disorder. We study their behavior in molecular dynamics simulations under elongational strain. In our analysis we compare the measured, purely entropic shear moduli G to the predictions of statistical mechanical models of rubber elasticity, making extensive use of the microscopic structural and topological information available in computer simulations. We find (Everaers and Kremer 1995) that the classical models of rubber elasticity underestimate the true change in entropy in a deformed network significantly, because they neglect the tension along the contour of the strands which cannot relax due to entanglements (Everaers and Kremer (in preparation)). This contribution and the fluctuations in strained systems seem to be well described by the constrained mode model (Everaers 1998) which allows to treat the crossover from classical rubber elasticity to the tube model for polymer networks with increasing strand length within one transparant formalism. While this is important for the description of the effects we try to do a first quantitative step towards their explanation by topological considerations. We show (Everaers and Kremer 1996a) that for the comparatively short strand lengths of our diamond networks the topology contribution to the shear modulus is proportional to the density of entangled mesh pairs with non-zero Gauss linking number. Moreover, the prefactor can be estimated consistently within a rather simple model developed by Vologodskii et al. and by Graessley and Pearson, which is based on the definition of an entropic
ACOUSTIC EFFECTS ON BINARY AEROELASTICITY MODEL
Directory of Open Access Journals (Sweden)
Kok Hwa Yu
2011-10-01
Full Text Available Acoustics is the science concerned with the study of sound. The effects of sound on structures attract overwhelm interests and numerous studies were carried out in this particular area. Many of the preliminary investigations show that acoustic pressure produces significant influences on structures such as thin plate, membrane and also high-impedance medium like water (and other similar fluids. Thus, it is useful to investigate the structure response with the presence of acoustics on aircraft, especially on aircraft wings, tails and control surfaces which are vulnerable to flutter phenomena. The present paper describes the modeling of structural-acoustic interactions to simulate the external acoustic effect on binary flutter model. Here, the binary flutter model which illustrated as a rectangular wing is constructed using strip theory with simplified unsteady aerodynamics involving flap and pitch degree of freedom terms. The external acoustic excitation, on the other hand, is modeled using four-node quadrilateral isoparametric element via finite element approach. Both equations then carefully coupled and solved using eigenvalue solution. The mentioned approach is implemented in MATLAB and the outcome of the simulated result are later described, analyzed and illustrated in this paper.
Magnetic field screening effect in electroweak model
Bakry, A; Zhang, P M; Zou, L P
2014-01-01
It is shown that in the Weinberg-Salam model a magnetic field screening effect for static magnetic solutions takes place. The origin of that phenomenon is conditioned by features of the electro-weak interaction, namely, there is mutual cancellation of Abelian magnetic fields created by the SU(2) gauge fields and Higgs boson. The effect implies monopole charge screening in finite energy system of monopoles and antimonopoles. We consider another manifestation of the screening effect which leads to an essential energy decrease of magnetic solutions. Applying variational method we have found a magnetic field configuration with a topological azimuthal magnetic flux which minimizes the energy functional and possesses a total energy of order 1 TeV. We suppose that corresponding magnetic bound state exists in the electroweak theory and can be detected in experiment.
Carcinogenic effects in a phenylketonuria mouse model.
Directory of Open Access Journals (Sweden)
Neil Sidell
Full Text Available Phenylketonuria (PKU is a metabolic disorder caused by impaired phenylalanine hydroxylase (PAH. This condition results in hyperphenylalaninemia and elevated levels of abnormal phenylalanine metabolites, among which is phenylacetic acid/phenylacetate (PA. In recent years, PA and its analogs were found to have anticancer activity against a variety of malignancies suggesting the possibility that PKU may offer protection against cancer through chronically elevated levels of PA. We tested this hypothesis in a genetic mouse model of PKU (PAH(enu2 which has a biochemical profile that closely resembles that of human PKU. Plasma levels of phenylalanine in homozygous (HMZ PAH(enu2 mice were >12-fold those of heterozygous (HTZ littermates while tyrosine levels were reduced. Phenylketones, including PA, were also markedly elevated to the range seen in the human disease. Mice were subjected to 7,12 dimethylbenz[a]anthracene (DMBA carcinogenesis, a model which is sensitive to the anticancer effects of the PA derivative 4-chlorophenylacetate (4-CPA. Tumor induction by DMBA was not significantly different between the HTZ and HMZ mice, either in total tumor development or in the type of cancers that arose. HMZ mice were then treated with 4-CPA as positive controls for the anticancer effects of PA and to evaluate its possible effects on phenylalanine metabolism in PKU mice. 4-CPA had no effect on the plasma concentrations of phenylalanine, phenylketones, or tyrosine. Surprisingly, the HMZ mice treated with 4-CPA developed an unexplained neuromuscular syndrome which precluded its use in these animals as an anticancer agent. Together, these studies support the use of PAH(enu2 mice as a model for studying human PKU. Chronically elevated levels of PA in the PAH(enu2 mice were not protective against cancer.
Dual coupling effective band model for polarons
Marchand, Dominic J. J.; Stamp, Philip C. E.; Berciu, Mona
2017-01-01
Nondiagonal couplings to a bosonic bath completely change polaronic dynamics, from the usual diagonally coupled paradigm of smoothly varying properties. We study, using analytic and numerical methods, a model having both diagonal Holstein and nondiagonal Su-Schrieffer-Heeger (SSH) couplings. The critical coupling found previously in the pure SSH model, at which the k =0 effective mass diverges, now becomes a transition line in the coupling constant plane—the form of the line depends on the adiabaticity parameter. Detailed results are given for the quasiparticle and ground-state properties, over a wide range of couplings and adiabaticity ratios. The new paradigm involves a destabilization, at the transition line, of the simple Holstein polaron to one with a finite ground-state momentum, but with everywhere a continuously evolving band shape. No "self-trapping transition" exists in any of these models. The physics may be understood entirely in terms of competition between different hopping terms in a simple renormalized effective band theory. The possibility of further transitions is suggested by the results.
Effects of verbenalin on prostatitis mouse model
Miao, Mingsan; Guo, Lin; Yan, Xiaoli; Wang, Tan; Li, Zuming
2015-01-01
The aim of this study was to observe the treatment characteristics of verbenalin on a prostatitis mouse model. Give Xiaozhiling injection in the prostate locally to make a prostatitis mouse model. High, medium and low doses of verbenalin were each given to different mouse groups. The amount of water was determined in 14th, 28th. The number of white cells and lecithin corpuscle density in prostatic fluid were determined. Morphological changes in the prostate, testis, epididymis and kidney were detected. Compared with the model control group, the mice treated with high, medium and low doses of verbenalin had significantly increased amounts of water, and prostate white blood cell count and prostate volume density (Vv) were decreased significantly, the density of lecithin corpuscle score increased, and pathologic prostatitis changes were significantly reduced. Pathological change in the testis was significantly reduced and the change in the epididymis was obviously reduced. The thymic cortex thickness and the number of lymphocytes increased significantly and could reduce the renal pathological changes in potential. Verbenalin has a good therapeutic effect on the prostatitis mouse model. PMID:26858560
Behavioral effects in room evacuation models
Dossetti, V.; Bouzat, S.; Kuperman, M. N.
2017-08-01
In this work we study a model for the evacuation of pedestrians from an enclosure considering a continuous space substrate and discrete time. We analyze the influence of behavioral features that affect the use of the empty space, that can be linked to the attitudes or characters of the pedestrians. We study how the interaction of different behavioral profiles affects the needed time to evacuate completely a room and the occurrence of clogging. We find that neither fully egotistic nor fully cooperative attitudes are optimal from the point of view of the crowd. In contrast, intermediate behaviors provide lower evacuation times. This leads us to identify some phenomena closely analogous to the faster-is-slower effect. The proposed model allows for distinguishing between the role of the attitudes in the search for empty space and the attitudes in the conflicts.
AN EFFECTIVE HUMAN LEG MODELING METHOD
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Digital medicine is a new concept in medical field, and the need for digital human body is increasing these years. This paper used Free Form Deformation (FFD) to model the motion of human leg. It presented the motion equations of knee joint on the basis of anatomic structure and motion characters, then transmitted the deformation to the mesh of leg through a simplified FFD that only used two-order B-spline basis function. The experiments prove that this method can simulate the bend of leg and the deformation of muscles fairly well. Compared with the method of curved patches, this method is more convenient and effective. Further more, those equations can be easily applied to other joint models of human body.
1994-01-01
This model of the Boeing A/FX (Advanced Attack/Fighter) Aircraft was photographed between test runs in NASA Langley Research Center's 16-Foot Transonic Tunnel. Testing was conducted to determine the effects of the jet exhaust on the aerodynamic characteristics of the aircraft afterbody. The A/FX program was a Navy effort to obtain a next-generation replacement for the A-6 and F/A-18. The A/FX program evolved into the current multi-service JSF (Joint Strike Fighter) program.
Modelling heating effects in cryocooled protein crystals
Nicholson, J; Fayz, K; Fell, B; Garman, E
2001-01-01
With the application of intense X-ray beams from third generation synchrotron sources, damage to cryocooled macromolecular crystals is being observed more commonly . In order to fully utilize synchrotron facilities now available for studying biological crystals, it is essential to understand the processes involved in radiation damage and beam heating so that, if possible, action can be taken to slow the rate of damage. Finite Element Analysis (FEA) has been applied to model the heating effects of X-rays on cryocooled protein crystals, and to compare the relative cooling efficiencies of nitrogen and helium.
An antenna model for the Purcell effect.
Krasnok, Alexander E; Slobozhanyuk, Alexey P; Simovski, Constantin R; Tretyakov, Sergei A; Poddubny, Alexander N; Miroshnichenko, Andrey E; Kivshar, Yuri S; Belov, Pavel A
2015-08-10
The Purcell effect is defined as a modification of the spontaneous emission rate of a quantum emitter at the presence of a resonant cavity. However, a change of the emission rate of an emitter caused by an environment has a classical counterpart. Any small antenna tuned to a resonance can be described as an oscillator with radiative losses, and the effect of the environment on its radiation can be modeled and measured in terms of the antenna radiation resistance, similar to a quantum emitter. We exploit this analogue behavior to develop a general approach for calculating the Purcell factors of different systems and various frequency ranges including both electric and magnetic Purcell factors. Our approach is illustrated by a general equivalent scheme, and it allows resenting the Purcell factor through the continuous radiation of a small antenna at the presence of an electromagnetic environment.
Speciation Effect in the Penna Aging Model
Łaszkiewicz, A.; Szymczak, Sz.; Cebrat, S.
We have simulated the evolution of diploid, sexually reproducing populations using the Penna model of aging. We have noted that diminishing the recombination frequency during the gamete production generates a specific diversity of genomes in the populations. When two populations independently evolving for some time were mixed in one environmental niche of the limited size and crossbreeding between them was allowed, the average lifespan of hybrids was significantly shorter than the lifespan of the individuals of parental lines. Another effect of higher hybrid mortality is the faster elimination of one parental line from the shared environment. The two populations living in one environment co-exist much longer if they are genetically separated — they compete as two species instead of crossbreeding. This effect can be considered as the first step to speciation — any barrier eliminating crossbreeding between these populations, leading to speciation, would favor the populations.
The Ranque-Hilsch effect: CFD modeling
Energy Technology Data Exchange (ETDEWEB)
Bezprozvannykh, V.; Mottl, H. [DYCOR Technologies, Edmonton, Alberta (Canada)]. E-mail: vlad.bez@dycor.com; hank.mottl@dycor.com
2003-07-01
The phenomenon of noticeable temperature distribution in confined steady rotating gas flows is referred as Ranque-Hilsch effect. The simple counter-flow Ranque-Hilsch tube consists of a long hollow cylinder with tangential nozzles at one end for injecting compressed gas. Rotating gas escapes the tube through two outlets - a central orifice diaphragm placed near the injection nozzle plane (cold stream) and a ring-shaped peripheral outlet placed at the opposite end of the tube (hot stream). The flow is essentially three-dimensional, turbulent, compressible, and spinning such that any theoretical simplifications are questionable, if at all possible. Fluent suite of software was applied at Dycor Technologies, Canada to the task of numerical simulation of the Ranque-Hilsch effect that is part of Dycor's program of fundamental and applied research. The behavior of two types of fluids in the Ranque-Hilsch tube was investigated - air and water. Three-dimensional continuity, momentum, and energy equations were solved for incompressible and compressible flows for water and air cases correspondingly. The Reynolds stress turbulence model was originally applied to close the Reynolds-averaged Navier-Stokes equations. The visualization of the velocity and temperature fields inside the vortex tube helped to understand the details of fluid flow. It was shown that CFD approach is applicable for simulating Ranque-Hilsch effect. It was found that various levels of complexity in turbulence modeling are suitable for vortex tube analysis. No vortex effect was observed for incompressible flow. The dependence of vortex tube cooling ability on initial gas pressure was investigated. Numerical simulation data are consistent with available experimental results. (author)
Modeling terahertz heating effects on water
DEFF Research Database (Denmark)
Kristensen, Torben T.L.; Withayachumnankul, Withawat; Jepsen, Peter Uhd;
2010-01-01
We apply Kirchhoff’s heat equation to model the influence of a CW terahertz beam on a sample of water, which is assumed to be static. We develop a generalized model, which easily can be applied to other liquids and solids by changing the material constants. If the terahertz light source is focused...... down to a spot with a diameter of 0.5 mm, we find that the steadystate temperature increase per milliwatt of transmitted power is 1.8◦C/mW. A quantum cascade laser can produce a CW beam in the order of several milliwatts and this motivates the need to estimate the effect of beam power on the sample...... temperature. For THz time domain systems, we indicate how to use our model as a worst-case approximation based on the beam average power. It turns out that THz pulses created from photoconductive antennas give a negligible increase in temperature. As biotissue contains a high water content, this leads...
Simple model of the slingshot effect
Directory of Open Access Journals (Sweden)
Gaetano Fiore
2016-07-01
Full Text Available We present a detailed quantitative description of the recently proposed “slingshot effect.” Namely, we determine a broad range of conditions under which the impact of a very short and intense laser pulse normally onto a low-density plasma (or matter locally completely ionized into a plasma by the pulse causes the expulsion of a bunch of surface electrons in the direction opposite to the one of propagation of the pulse, and the detailed, ready-for-experiments features of the expelled electrons (energy spectrum, collimation, etc. The effect is due to the combined actions of the ponderomotive force and the huge longitudinal field arising from charge separation. Our predictions are based on estimating 3D corrections to a simple, yet powerful plane 2-fluid magnetohydrodynamic (MHD model where the equations to be solved are reduced to a system of Hamilton equations in one dimension (or a collection of which become autonomous after the pulse has overcome the electrons. Experimental tests seem to be at hand. If confirmed by the latter, the effect would provide a new extraction and acceleration mechanism for electrons, alternative to traditional radio-frequency-based or Laser-Wake-Field ones.
Modeling Instruction: An Effective Model for Science Education
Jackson, Jane; Dukerich, Larry; Hestenes, David
2008-01-01
The authors describe a Modeling Instruction program that places an emphasis on the construction and application of conceptual models of physical phenomena as a central aspect of learning and doing science. (Contains 1 table.)
[Effect evaluation of three cell culture models].
Wang, Aiguo; Xia, Tao; Yuan, Jing; Chen, Xuemin
2003-11-01
Primary rat hepatocytes were cultured using three kinds of models in vitro and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH in the medium decreased over time in the period of culture. However, on 5 days, LDH showed a significant increase in monolayer culture (MC) while after 8 days LDH was not detected in sandwich culture (SC). The levels of AST and ALT in the medium did not change significantly over the investigated time. The basic CYP 1A activity gradually decreased with time in MC and SC. The decline of CYP 1A in rat hepatocytes was faster in MC than that in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducers such as omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than that in SC. Basic CYP 1A activity in bioreactor was keeped over 2 weeks and the highest albumin production was observed in bioreactor, and next were SC and MC. In conclusion, our results clearly indicated that there have some advantages and disadvantages in each of models in which can address different questions in metabolism of toxicants and drugs.
Effectiveness of Peer Education Involving the use of Theoretical Models
2008-01-01
The effectiveness of health education among university students who received peer-support training was investigated using four theoretical models : the health belief model, the self-efficacy model, social support and the transtheoretical model of health behavior change. Results suggested that the four theoretical models were useful in evaluating the effect of peer education as an alternative assessment tool. In light of this, it is suggested that the use of the theoretical models may facilita...
A simple model of the slingshot effect
Fiore, Gaetano
2015-01-01
We present a detailed quantitative description of the recently proposed "slingshot effect" [Fiore, Fedele, De angelis 2014]. Namely, we determine a broad range of conditions under which the impact of a very short and intense laser pulse normally onto a plasma (or matter to be locally completely ionized into a plasma by the pulse) causes the expulsion of a bunch of surface electrons in the direction opposite to the one of propagation of the pulse, and the detailed, ready-for-experiments features of the expelled electrons (energy spectrum, collimation, etc). The effect is due to the combined actions of the ponderomotive force and the huge longitudinal field arising from charge separation. Our predictions are based on estimating 3D corrections to a simple, yet powerful plane magnetofluidodynamic model where the equations to be solved are reduced to a system of Hamilton equations in one dimension (or a collection of) which become autonomous after the pulse has overcome the electrons. Experimental tests seem to be...
Murphy, Daniel L.; Beretvas, S. Natasha
2015-01-01
This study examines the use of cross-classified random effects models (CCrem) and cross-classified multiple membership random effects models (CCMMrem) to model rater bias and estimate teacher effectiveness. Effect estimates are compared using CTT versus item response theory (IRT) scaling methods and three models (i.e., conventional multilevel…
Wake effects and wind farm modelling
Energy Technology Data Exchange (ETDEWEB)
Crespo, A.; Gomez-Elvira, R. [Univ. Politecnica de Madrid, Dept. of Energy and Fluid Mechanic (Spain)
1999-07-01
A model has been developed to treat simultaneously the changes in wind characteristics due to the transition from land to sea, and the wake effects in offshore wind farms. There are beneficial effects both in an increase of power production and in a reduction of turbulence loads when the distance from the farm to the land coast is increased, however, particularly for the turbulence loads, this effect reaches a limit beyond a certain distance of the order of 1 to 2 km. A method has been proposed to estimate the performance of offshore wind farms, that has been applied to places of interest to the project. As it was observed in the project East Coast of the UK, wake effects are important and significant increases can be obtained in power production by increasing the distance between machines and a better disposition of them, i.e. alternating positions in contiguous rows normal to the prevailing wind direction. The most efficient wind farms from the point of view of wake interference are Gedser and Omo with an efficiency of 89% and 86% respectively. A large wind farm like Rodsand has lower efficiency because of the cumulative effect of the wakes of many turbines. The calculated value of the capacity factor of the three Danish wind farms is larger than 36%. The value of the added turbulence intensity, averaged over rows normal to the incident wind, increases suddenly in the first rows and then reaches an almost constant value in the downstream rows, that is of the order of 10%. A method to calculate the performance of very large wind farms, such that they can change the planetary boundary layer is presented. This method has been applied to the wind farms of interest in the project, and small reductions of the order of 5% or less in power production may occur. However, for very large wind farms (with a of the order of 100 km), that may perturb the whole planetary boundary layer, much more drastic reductions, of the order of 50%, may appear, particularly in the
[Effect of astaxanthin on preeclampsia rat model].
Xuan Rong-rong; Gao Xin; Wu, Wei; Chen, Hai-min
2014-10-01
The effect of astaxanthin on N(Ω)-nitro-L-arginine methyl ester (L-NAME) induced preeclampsia disease rats was investigated. Thirty pregnant Sprague-Dawley rats were randomly divided into three groups (n = 10): blank group, L-NAME group and astaxanthin group. From day 5 to 20, astaxanthin group rats were treated with astaxanthin (25 mg x kg(-1) x d(-1) x bw(-1)) from pregnancy (day 5). To establish the preeclamptic rat model, L-NAME group and astaxanthin group rats were injected with L-NAME (125 mg x kg(-1) x d(-1) x bw(-1)) from days 10-20 of pregnancy. The blood pressure and urine protein were recorded. Serum of each group was collected and malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide synthase (NOS) activities were analyzed. Pathological changes were observed with HE stain. The expression of NF-κB (nuclear factor kappa B), ROCK II (Rho-associated protein kinase II), HO-1 (heme oxygenase-1) and Caspase 3 were analyzed with immunohistochemistry. L-NAME induced typical preeclampsia symptoms, such as the increased blood pressure, urinary protein, the content of MDA, etc. Astaxanthin significantly reduced the blood pressure (P astaxanthin, the thickness of basilal membrane was improved and the content of trophoblast cells and spiral arteries was reduced. Immunohistochemistry results revealed that the expressions of NF-κB, ROCK II and Caspase 3 in placenta tissue were effectively decreased, and HO-1 was increased. Results indicated that astaxanthin can improve the preeclampsia symptoms by effectively reducing the oxidative stress and inflammatory damages of preeclampsia. It revealed that astaxanthin may be benefit for prevention and treatment of preeclampsia disease.
Assessing NARCCAP climate model effects using spatial confidence regions
French, Joshua P.; McGinnis, Seth; Schwartzman, Armin
2017-07-01
We assess similarities and differences between model effects for the North American Regional Climate Change Assessment Program (NARCCAP) climate models using varying classes of linear regression models. Specifically, we consider how the average temperature effect differs for the various global and regional climate model combinations, including assessment of possible interaction between the effects of global and regional climate models. We use both pointwise and simultaneous inference procedures to identify regions where global and regional climate model effects differ. We also show conclusively that results from pointwise inference are misleading, and that accounting for multiple comparisons is important for making proper inference.
Assessing NARCCAP climate model effects using spatial confidence regions
Directory of Open Access Journals (Sweden)
J. P. French
2017-07-01
Full Text Available We assess similarities and differences between model effects for the North American Regional Climate Change Assessment Program (NARCCAP climate models using varying classes of linear regression models. Specifically, we consider how the average temperature effect differs for the various global and regional climate model combinations, including assessment of possible interaction between the effects of global and regional climate models. We use both pointwise and simultaneous inference procedures to identify regions where global and regional climate model effects differ. We also show conclusively that results from pointwise inference are misleading, and that accounting for multiple comparisons is important for making proper inference.
A random effects epidemic-type aftershock sequence model.
Lin, Feng-Chang
2011-04-01
We consider an extension of the temporal epidemic-type aftershock sequence (ETAS) model with random effects as a special case of a well-known doubly stochastic self-exciting point process. The new model arises from a deterministic function that is randomly scaled by a nonnegative random variable, which is unobservable but assumed to follow either positive stable or one-parameter gamma distribution with unit mean. Both random effects models are of interest although the one-parameter gamma random effects model is more popular when modeling associated survival times. Our estimation is based on the maximum likelihood approach with marginalized intensity. The methods are shown to perform well in simulation experiments. When applied to an earthquake sequence on the east coast of Taiwan, the extended model with positive stable random effects provides a better model fit, compared to the original ETAS model and the extended model with one-parameter gamma random effects.
Effective stimuli for constructing reliable neuron models.
Directory of Open Access Journals (Sweden)
Shaul Druckmann
2011-08-01
Full Text Available The rich dynamical nature of neurons poses major conceptual and technical challenges for unraveling their nonlinear membrane properties. Traditionally, various current waveforms have been injected at the soma to probe neuron dynamics, but the rationale for selecting specific stimuli has never been rigorously justified. The present experimental and theoretical study proposes a novel framework, inspired by learning theory, for objectively selecting the stimuli that best unravel the neuron's dynamics. The efficacy of stimuli is assessed in terms of their ability to constrain the parameter space of biophysically detailed conductance-based models that faithfully replicate the neuron's dynamics as attested by their ability to generalize well to the neuron's response to novel experimental stimuli. We used this framework to evaluate a variety of stimuli in different types of cortical neurons, ages and animals. Despite their simplicity, a set of stimuli consisting of step and ramp current pulses outperforms synaptic-like noisy stimuli in revealing the dynamics of these neurons. The general framework that we propose paves a new way for defining, evaluating and standardizing effective electrical probing of neurons and will thus lay the foundation for a much deeper understanding of the electrical nature of these highly sophisticated and non-linear devices and of the neuronal networks that they compose.
Effective and efficient model clone detection
DEFF Research Database (Denmark)
Störrle, Harald
2015-01-01
Code clones are a major source of software defects. Thus, it is likely that model clones (i.e., duplicate fragments of models) have a significant negative impact on model quality, and thus, on any software created based on those models, irrespective of whether the software is generated fully...... automatically (“MDD-style”) or hand-crafted following the blueprint defined by the model (“MBSD-style”). Unfortunately, however, model clones are much less well studied than code clones. In this paper, we present a clone detection algorithm for UML domain models. Our approach covers a much greater variety...... of model types than existing approaches while providing high clone detection rates at high speed....
Cheung, Mike W.-L.; Cheung, Shu Fai
2016-01-01
Meta-analytic structural equation modeling (MASEM) combines the techniques of meta-analysis and structural equation modeling for the purpose of synthesizing correlation or covariance matrices and fitting structural equation models on the pooled correlation or covariance matrix. Both fixed-effects and random-effects models can be defined in MASEM.…
Mixed effects in stochastic differential equation models
DEFF Research Database (Denmark)
Ditlevsen, Susanne; De Gaetano, Andrea
2005-01-01
maximum likelihood; pharmacokinetics; population estimates; random effects; repeated measurements; stochastic processes......maximum likelihood; pharmacokinetics; population estimates; random effects; repeated measurements; stochastic processes...
Simulation modeling of outcomes and cost effectiveness.
Ramsey, S D; McIntosh, M; Etzioni, R; Urban, N
2000-08-01
Modeling will continue to be used to address important issues in clinical practice and health policy issues that have not been adequately studied with high-quality clinical trials. The apparent ad hoc nature of models belies the methodologic rigor that is applied to create the best models in cancer prevention and care. Models have progressed from simple decision trees to extremely complex microsimulation analyses, yet all are built using a logical process based on objective evaluation of the path between intervention and outcome. The best modelers take great care to justify both the structure and content of the model and then test their assumptions using a comprehensive process of sensitivity analysis and model validation. Like clinical trials, models sometimes produce results that are later found to be invalid as other data become available. When weighing the value of models in health care decision making, it is reasonable to consider the alternatives. In the absence of data, clinical policy decisions are often based on the recommendations of expert opinion panels or on poorly defined notions of the standard of care or medical necessity. Because such decision making rarely entails the rigorous process of data collection, synthesis, and testing that is the core of well-conducted modeling, it is usually not possible for external audiences to examine the assumptions and data that were used to derive the decisions. One of the modeler's most challenging tasks is to make the structure and content of the model transparent to the intended audience. The purpose of this article is to clarify the process of modeling, so that readers of models are more knowledgeable about their uses, strengths, and limitations.
Nonlinear Mixed-Effects Models for Repairable Systems Reliability
Institute of Scientific and Technical Information of China (English)
TAN Fu-rong; JIANG Zhi-bin; KUO Way; Suk Joo BAE
2007-01-01
Mixed-effects models, also called random-effects models, are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject, but also to describe the variation among different subjects. Nonlinear mixed-effects models provide a powerful and flexible tool for handling the unbalanced count data. In this paper, nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple copies. By using this type of models, statistical inferences about the population and all copies can be made when accounting for copy-to-copy variance. Results of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.
Receiver Prejudice and Model Ethnicity: Impact on Advertising Effectiveness.
Lai, Hsiu-Chen Sandra; And Others
1990-01-01
Assesses the effect of model ethnicity on prejudiced respondents, and thus on advertising effectiveness. Finds that, for the most part, use of Asian models does not cause prejudiced respondents to evaluate a product or advertisement more negatively than when White models are used. (SR)
Receiver Prejudice and Model Ethnicity: Impact on Advertising Effectiveness.
Lai, Hsiu-Chen Sandra; And Others
1990-01-01
Assesses the effect of model ethnicity on prejudiced respondents, and thus on advertising effectiveness. Finds that, for the most part, use of Asian models does not cause prejudiced respondents to evaluate a product or advertisement more negatively than when White models are used. (SR)
Numerical modeling of 3-D terrain effect on MT field
Institute of Scientific and Technical Information of China (English)
徐世浙; 阮百尧; 周辉; 陈乐寿; 徐师文
1997-01-01
Using the boundary element method, the numerical modeling problem of three-dimensional terrain effect on magnetotelluric (MT) field is solved. This modeling technique can be run on PC in the case of adopting special net division. The result of modeling test for 2-D terrain by this modeling technique is basically coincident with that by 2-D modeling technique, but there is a great difference between the results of 3-D and 2-D modeling for 3-D terrain.
Nanoindentation shape effect: experiments, simulations and modelling
Energy Technology Data Exchange (ETDEWEB)
Calabri, L [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Pugno, N [Department of Structural Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Rota, A [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Marchetto, D [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Valeri, S [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy)
2007-10-03
AFM nanoindentation is nowadays commonly used for the study of mechanical properties of materials at the nanoscale. The investigation of surface hardness of a material using AFM means that the probe has to be able to indent the surface, but also to image it. Usually standard indenters are not sharp enough to obtain high-resolution images, but on the other hand measuring the hardness behaviour of a material with a non-standard sharp indenter gives only comparative results affected by a significant deviation from the commonly used hardness scales. In this paper we try to understand how the shape of the indenter affects the hardness measurement, in order to find a relationship between the measured hardness of a material and the corner angle of a pyramidal indenter. To achieve this we performed a full experimental campaign, indenting the same material with three focused ion beam (FIB) nanofabricated probes with a highly altered corner angle. We then compared the results obtained experimentally with those obtained by numerical simulations, using the finite element method (FEM), and by theoretical models, using a general scaling law for nanoindentation available for indenters with a variable size and shape. The comparison between these three approaches (experimental, numerical and theoretical approaches) reveals a good agreement and allowed us to find a theoretical relationship which links the measured hardness value with the shape of the indenter. The same theoretical approach has also been used to fit the hardness experimental results considering the indentation size effect. In this case we compare the measured data, changing the applied load.
Multivariate Term Structure Models with Level and Heteroskedasticity Effects
DEFF Research Database (Denmark)
Christiansen, Charlotte
2005-01-01
The paper introduces and estimates a multivariate level-GARCH model for the long rate and the term-structure spread where the conditional volatility is proportional to the ãth power of the variable itself (level effects) and the conditional covariance matrix evolves according to a multivariate...... GARCH process (heteroskedasticity effects). The long-rate variance exhibits heteroskedasticity effects and level effects in accordance with the square-root model. The spread variance exhibits heteroskedasticity effects but no level effects. The level-GARCH model is preferred above the GARCH model...... and the level model. GARCH effects are more important than level effects. The results are robust to the maturity of the interest rates. Udgivelsesdato: MAY...
Modeling Potentially Time-Varying Effects of Promotions on Sales
Ph.H.B.F. Franses (Philip Hans); R. Paap (Richard); Ph.A. Sijthoff
2001-01-01
textabstractA commonly applied modeling tool for the analysis of promotional effects on weekly sales data is a linear regression model. Usually, such a model includes 0/1 dummy variables for promotions, where weeks with a promotion get a value of 1. When these variables are included in a model with
Ashraf, Giti; Kadir, Suhaida bte Abd
2012-01-01
Organizational effectiveness is the main concern of all higher education institutes. Over the years there have been many different models of effectiveness along with the criteria for measuring organizational effectiveness. In this paper, four main models of organizational effectiveness namely the goal approach, the system resource approach, the…
Organizational effectiveness of coalition operations' headquarters : A theoretical model
Vogler-Bisig, E.; Blais, A.R.; Hof, T.; Tresch, T.S.; Seiler, S.; Yanakiev, Y.
2012-01-01
Purpose - This article describes a theoretical model that allows understanding, explaining, and measuring the perceived organizational effectiveness of multinational coalition operations' headquarters. Design/methodology/approach - The proposed model is based on subject matter experts' opinions and
Effect of GPS errors on Emission model
DEFF Research Database (Denmark)
Lehmann, Anders; Gross, Allan
n this paper we will show how Global Positioning Services (GPS) data obtained from smartphones can be used to model air quality in urban settings. The paper examines the uncertainty of smartphone location utilising GPS, and ties this location uncertainty to air quality models. The results presented...
Incorporating Context Effects into a Choice Model
Rooderkerk, Robert P.; Van Heerde, Harald J.; Bijmolt, Tammo H. A.
The behavioral literature provides ample evidence that consumer preferences are partly driven by the context provided by the set of alternatives. Three important context effects are the compromise, attraction, and similarity effects. Because these context effects affect choices in a systematic and
Incorporating Context Effects into a Choice Model
Rooderkerk, Robert P.; Van Heerde, Harald J.; Bijmolt, Tammo H. A.
2011-01-01
The behavioral literature provides ample evidence that consumer preferences are partly driven by the context provided by the set of alternatives. Three important context effects are the compromise, attraction, and similarity effects. Because these context effects affect choices in a systematic and p
Integrating teacher education effectiveness research into educational effectiveness models
Scheerens, Jaap; Blömeke, Sigrid
2016-01-01
The purpose of this article is to review and to connect research about teacher education effectiveness and school effectiveness to arrive at an integrative conceptualization that has the potential of improving empirical research in both fields. Teacher education effectiveness addresses effects of te
Integrating teacher education effectiveness research into educational effectiveness models
Scheerens, Jaap; Blömeke, Sigrid
2016-01-01
The purpose of this article is to review and to connect research about teacher education effectiveness and school effectiveness to arrive at an integrative conceptualization that has the potential of improving empirical research in both fields. Teacher education effectiveness addresses effects of
Review of health effects models for Level 3 PSA
Energy Technology Data Exchange (ETDEWEB)
Lee, Seung Hee; Kim, Ju Youl [FNC Technology Co., Yongin (Korea, Republic of); Han, Seok Jung [KAERI, Daejeon (Korea, Republic of)
2016-05-15
Many international organizations have developed health risk models. Especially, as radiation-induced cancer is an important part among health effects, development has been focused on cancer risk model. This paper reviewed the cancer risk models of international agencies; United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), National Academy of Sciences (NAS) and International Commission on Radiological Protection (ICRP). Moreover, as pre-research for improving the health risk model in Korea, this paper analyzed the three methodologies and specific details in modeling. International agencies have developed radiation-induced cancer risk model reflecting the recent A-bomb survivor LSS data. This paper reviewed the recent cancer risk model of UNSCEAR, NAS and ICRP. All three models were based on ERR and EAR model in the form of a multiplication of dose-response model and modification function. Lifetime risk was calculated as a function of exposure age and gender.
Advertising effects in Sznajd marketing model
Christian Schulze
2002-01-01
The traditional Sznajd model, as well as its Ochrombel simplification for opinion spreading, are applied to marketing with the help of advertising. The larger the lattice is the smaller is the amount of advertising needed to convince the whole market
Tsai, Chia-Ching; Chang, Chih-Hsiang
2007-01-01
This study investigates the effect of advertising with physically attractive models on male and female adolescents. The findings suggest that highly attractive models are less effective than those who are normally attractive. Implications of social comparison are discussed.
Tsai, Chia-Ching; Chang, Chih-Hsiang
2007-01-01
This study investigates the effect of advertising with physically attractive models on male and female adolescents. The findings suggest that highly attractive models are less effective than those who are normally attractive. Implications of social comparison are discussed.
Effect of mobility models on infrastructure based wireless networks ...
African Journals Online (AJOL)
Effect of mobility models on infrastructure based wireless networks. ... In this paper, the effect of handoff procedure on the performance of random mobile nodes in wireless networks was investigated. Mobility of node is defined ... Article Metrics.
Modelling Effectiveness of Machine Gun Fire
Dutta, D.; S. Sabhanval
2002-01-01
Machine gun is an effective infantry weapon which can cause heavy damage to enemy targets, if sited in a tactically favourable position. It can be engaged effectively against both static and moving targets. The paper deals with the determination of target vulnerability under effective machine gun fire considering relevant tactical parameters, eg, target aiming point, trajectory of fire, sweep angle, target frontage, posture, direction of attack, etc.
Modelling Effectiveness of Machine Gun Fire
Directory of Open Access Journals (Sweden)
D. Dutta
2002-04-01
Full Text Available Machine gun is an effective infantry weapon which can cause heavy damage to enemy targets, if sited in a tactically favourable position. It can be engaged effectively against both static and moving targets. The paper deals with the determination of target vulnerability under effective machine gun fire considering relevant tactical parameters, eg, target aiming point, trajectory of fire, sweep angle, target frontage, posture, direction of attack, etc.
Multilevel Modeling of Item Position Effects
Albano, Anthony D.
2013-01-01
In many testing programs it is assumed that the context or position in which an item is administered does not have a differential effect on examinee responses to the item. Violations of this assumption may bias item response theory estimates of item and person parameters. This study examines the potentially biasing effects of item position. A…
Model for Effective Contraceptive Counseling on Campus.
Bachmann, Gloria A.
1981-01-01
A study compared the effective v ineffective use of contraceptives at a major university by comparing college women who had experienced birth control failure with those who had not. Factors related to a woman's use of a contraceptive device include: satisfaction with its aesthetic properties; trust in its effectiveness; a feeling of comfort…
Hoogerheide, Vincent; van Wermeskerken, Margot; Loyens, Sofie M M; van Gog, Tamara
2016-01-01
Learning from (video) modeling examples in which a model demonstrates how to perform a task is an effective instructional strategy. The model-observer similarity (MOS) hypothesis postulates that (perceived) similarity between learners and the model in terms of age or expertise moderates the effectiv
Enhanced battery model including temperature effects
Rosca, B.; Wilkins, S.
2013-01-01
Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a dy
A Mixed Effects Randomized Item Response Model
Fox, J.-P.; Wyrick, Cheryl
2008-01-01
The randomized response technique ensures that individual item responses, denoted as true item responses, are randomized before observing them and so-called randomized item responses are observed. A relationship is specified between randomized item response data and true item response data. True item response data are modeled with a (non)linear…
Modelling irradiation effects in fusion materials
DEFF Research Database (Denmark)
Victoria, M.; Dudarev, S.; Boutard, J.L.;
2007-01-01
We review the current status of the European fusion materials modelling programme. We describe recent findings and outline potential areas for future development. Large-scale density functional theory (DFT) calculations reveal the structure of the point defects in α-Fe, and highlight the crucial...
Effective models for excitons in carbon nanotubes
DEFF Research Database (Denmark)
Cornean, Horia; Duclos, Pierre; Ricaud, Benjamin
2007-01-01
We analyse the low lying spectrum of a model of excitons in carbon nanotubes. Consider two particles with opposite charges and a Coulomb self-interaction, placed on an infinitely long cylinder. If the cylinder radius becomes small, the low lying spectrum of their relative motion is well described...
Enhanced battery model including temperature effects
Rosca, B.; Wilkins, S.
2013-01-01
Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a dy
Systems modelling for effective mine water management
Energy Technology Data Exchange (ETDEWEB)
Cote, C.M.; Moran, C.J.; Hedemann, C.J.; Koch, C. [University of Queensland, Brisbane, Qld. (Australia)
2010-12-15
Concerns about the difficulties in securing water have led the Australian coal mining industry to seek innovative ways to improve its water management and to adopt novel strategies that will lead to less water being used and more water being reused. Simulation tools are essential to assess current water management performance and to predict the efficiency of potential strategies. As water systems on coal mines are complex and consist of various inter-connected elements, a systems approach was selected, which views mine site water management as a system that obtains water from various sources (surface, groundwater), provides sufficient water of suitable quality to the mining tasks (coal beneficiation, dust suppression, underground operations) and maintains environmental performance. In this paper, the model is described and its calibration is illustrated. The results of applying the model for the comparison of the water balances of 7 coal mines in the northern Bowen Basin (Queensland, Australia) are presented. The model is used to assess the impact of applying specific water management strategies. Results show that a simple systems model is an appropriate tool for assessing site performance, for providing guidance to improve performance through strategic planning, and for guiding adoption of site objectives.
Enhanced battery model including temperature effects
Rosca, B.; Wilkins, S.
2013-01-01
Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a
Coriolis effects and motion sickness modelling.
Bles, W
1998-11-15
Coriolis effects are notorious in relation to disorientation and motion sickness in aircrew. A review is provided of experimental data on these Coriolis effects, including the modulatory effects of adding visual or somatosensory rotatory motion information. A vector analysis of the consequences of head movements during somatosensory, visual and/or vestibular rotatory motion stimulation revealed that the more the sensed angular velocity vector after the head movements is aligned with the gravitoinertial force vector, the less nauseating effects are experienced. It is demonstrated that this is a special case of the subjective vertical conflict theory on motion sickness that assumes that motion sickness may be provoked if a discrepancy is detected between the subjective vertical and the sensed vertical as determined on the basis of incoming sensory information.
Neural Networks for Electrohydrodynamic Effect Modelling
Directory of Open Access Journals (Sweden)
Jolanta Gancarz
2004-01-01
Full Text Available This paper presents currently achieved results concerning methods of electrohydrodynamic effect used in geophysics simulated with feedforward networks trained with backpropagation algorithm, radial basis function networks and generalized regression networks.
A random effects generalized linear model for reliability compositive evaluation
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
This paper first proposes a random effects generalized linear model to evaluate the storage life of one kind of high reliable and small sample-sized products by combining multi-sources information of products coming from the same population but stored at different environments. The relevant algorithms are also provided. Simulation results manifest the soundness and effectiveness of the proposed model.
Evaluating Differential Effects Using Regression Interactions and Regression Mixture Models
Van Horn, M. Lee; Jaki, Thomas; Masyn, Katherine; Howe, George; Feaster, Daniel J.; Lamont, Andrea E.; George, Melissa R. W.; Kim, Minjung
2015-01-01
Research increasingly emphasizes understanding differential effects. This article focuses on understanding regression mixture models, which are relatively new statistical methods for assessing differential effects by comparing results to using an interactive term in linear regression. The research questions which each model answers, their…
Modeling the effects of study abroad programs on college students
Alvin H. Yu; Garry E. Chick; Duarte B. Morais; Chung-Hsien Lin
2009-01-01
This study explored the possibility of modeling the effects of a study abroad program on students from a university in the northeastern United States. A program effect model was proposed after conducting an extensive literature review and empirically examining a sample of 265 participants in 2005. Exploratory factor analysis (EFA), confirmatory factor analysis (CFA),...
A random effects generalized linear model for reliability compositive evaluation
Institute of Scientific and Technical Information of China (English)
ZHAO Hui; YU Dan
2009-01-01
This paper first proposes a random effects generalized linear model to evaluate the storage life of one kind of high reliable and small sample-sized products by combining multi-sources information of products coming from the same population but stored at different environments.The relevant algorithms are also provided.Simulation results manifest the soundness and effectiveness of the proposed model.
Medical Surveillance System & Medical Effect Modeling Thrust Areas
2007-06-01
Equations ( PFE ) developed for this project model physiological systems in biological organisms as 1D liquid or gas flows. Special attention is given...in the model to capturing 2D viscous effects and branching effects. Multiple PFE representations of physiological systems (e.g. the respiratory and
A fiber-bridging model with stress gradient effects
Yi, Sun; Tao, Li
2000-05-01
A fiber-bridging model with stress gradient effects is proposed for unidirectional fiber-reinforced composites. The stress gradient terms are introduced by solving a micromechanical model under a non-uniform stress loading. It is shown that the stress gradient effect is significant on both the fiber-bridging stress distribution and the value of the critical load of fiber failure.
Modeling dynamic effects of promotion on interpurchase times
D. Fok (Dennis); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)
2002-01-01
textabstractIn this paper we put forward a duration model to analyze the dynamic effects of marketing-mix variables on interpurchase times. We extend the accelerated failure-time model with an autoregressive structure. An important feature of our model is that it allows for different long-run and
Modeling dynamic effects of promotion on interpurchase times
D. Fok (Dennis); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)
2002-01-01
textabstractIn this paper we put forward a duration model to analyze the dynamic effects of marketing-mix variables on interpurchase times. We extend the accelerated failure-time model with an autoregressive structure. An important feature of our model is that it allows for different long-run and
Effective Reading and Writing Instruction: A Focus on Modeling
Regan, Kelley; Berkeley, Sheri
2012-01-01
When providing effective reading and writing instruction, teachers need to provide explicit modeling. Modeling is particularly important when teaching students to use cognitive learning strategies. Examples of how teachers can provide specific, explicit, and flexible instructional modeling is presented in the context of two evidence-based…
Effects of Modeling and Reinforcement on Adult Chronic Schizophrenics
Olson, R. Paul
1971-01-01
This study confirmed two general predictions: (1) the model contributes to new learning; and (2) neither the model nor reinforcement of the model adds significantly to motivation, beyond the effect that can be attributed to reinforcement of the subject himself. (Author/CG)
Seventh Grade Students' Mental Models of the Greenhouse Effect
Shepardson, Daniel P.; Choi, Soyoung; Niyogi, Dev; Charusombat, Umarporn
2011-01-01
This constructivist study investigates 225 student drawings and explanations from three different schools in the midwest in the US, to identify seventh grade students' mental models of the greenhouse effect. Five distinct mental models were derived from an inductive analysis of the content of the students' drawings and explanations: Model 1, a…
A Gompertzian model with random effects to cervical cancer growth
Energy Technology Data Exchange (ETDEWEB)
Mazlan, Mazma Syahidatul Ayuni; Rosli, Norhayati [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia)
2015-05-15
In this paper, a Gompertzian model with random effects is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via maximum likehood estimation. We apply 4-stage Runge-Kutta (SRK4) for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of the cervical cancer growth. Low values of root mean-square error (RMSE) of Gompertzian model with random effect indicate good fits.
Environmental Radiation Effects on Mammals A Dynamical Modeling Approach
Smirnova, Olga A
2010-01-01
This text is devoted to the theoretical studies of radiation effects on mammals. It uses the framework of developed deterministic mathematical models to investigate the effects of both acute and chronic irradiation in a wide range of doses and dose rates on vital body systems including hematopoiesis, small intestine and humoral immunity, as well as on the development of autoimmune diseases. Thus, these models can contribute to the development of the system and quantitative approaches in radiation biology and ecology. This text is also of practical use. Its modeling studies of the dynamics of granulocytopoiesis and thrombocytopoiesis in humans testify to the efficiency of employment of the developed models in the investigation and prediction of radiation effects on these hematopoietic lines. These models, as well as the properly identified models of other vital body systems, could provide a better understanding of the radiation risks to health. The modeling predictions will enable the implementation of more ef...
Singlet model interference effects with high scale UV physics
Dawson, S.; Lewis, I. M.
2017-01-01
One of the simplest extensions of the Standard Model (SM) is the addition of a scalar gauge singlet, S . If S is not forbidden by a symmetry from mixing with the Standard Model Higgs boson, the mixing will generate non-SM rates for Higgs production and decays. In general, there could also be unknown high energy physics that generates additional effective low energy interactions. We show that interference effects between the scalar resonance of the singlet model and the effective field theory (EFT) operators can have significant effects in the Higgs sector. We examine a non-Z2 symmetric scalar singlet model and demonstrate that a fit to the 125 GeV Higgs boson couplings and to limits on high mass resonances, S , exhibit an interesting structure and possible large cancellations of effects between the resonance contribution and the new EFT interactions, that invalidate conclusions based on the renormalizable singlet model alone.
The media effect in Axelrod's model explained
Peres, Lucas R
2011-01-01
We revisit the problem of introducing an external global field -- the mass media -- in Axelrod's model of social dynamics, where in addition to their nearest neighbors, the agents can interact with a virtual neighbor whose cultural features are fixed from the outset. The finding that this apparently homogenizing field actually increases the cultural diversity has been considered a puzzle since the phenomenon was first reported more than a decade ago. Here we offer a simple explanation for it, which is based on the pedestrian observation that Axelrod's model exhibits more cultural diversity, i.e., more distinct cultural domains, when the agents are allowed to interact solely with the media field than when they can interact with their neighbors as well. In this perspective, it is the local homogenizing interactions that work towards making the absorbing configurations less fragmented as compared with the extreme situation in which the agents interact with the media only.
SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS
Vasilica Magdalena SOMEŞFĂLEAN
2014-01-01
Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits) over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed o...
Life course models: improving interpretation by consideration of total effects.
Green, Michael J; Popham, Frank
2016-12-28
Life course epidemiology has used models of accumulation and critical or sensitive periods to examine the importance of exposure timing in disease aetiology. These models are usually used to describe the direct effects of exposures over the life course. In comparison with consideration of direct effects only, we show how consideration of total effects improves interpretation of these models, giving clearer notions of when it will be most effective to intervene. We show how life course variation in the total effects depends on the magnitude of the direct effects and the stability of the exposure. We discuss interpretation in terms of total, direct and indirect effects and highlight the causal assumptions required for conclusions as to the most effective timing of interventions.
Richly parameterized linear models additive, time series, and spatial models using random effects
Hodges, James S
2013-01-01
A First Step toward a Unified Theory of Richly Parameterized Linear ModelsUsing mixed linear models to analyze data often leads to results that are mysterious, inconvenient, or wrong. Further compounding the problem, statisticians lack a cohesive resource to acquire a systematic, theory-based understanding of models with random effects.Richly Parameterized Linear Models: Additive, Time Series, and Spatial Models Using Random Effects takes a first step in developing a full theory of richly parameterized models, which would allow statisticians to better understand their analysis results. The aut
Effects of modeling means on properties of monitoring models of spot welding quality
Institute of Scientific and Technical Information of China (English)
张忠典; 李冬青; 赵洪运; 于燕
2002-01-01
Analyzing and modeling the relation between monitoring information during welding and quality information of the joints is the foundation of monitoring resistance spot welding quality. According to the means of modeling, the known models can be divided into three large categories: single linear regression models, multiple linear regression models and multiple non-linear models. By modeling the relations between dynamic resistance information and welding quality parameters with different means, this paper analyzes effects of modeling means on performances of monitoring models of resistance spot welding quality. From the test results, the following conclusions can be drawn: By comparison with two other kinds of models, artificial neural network (ANN) model can describe non-linear and high coupling relationship between monitoring information and quality information more reasonably, improve performance of monitoring model remarkably, and make the estimated values of welding quality parameters more accurate and reliable.
Towards effective food chains : models and applications
Trienekens, J.H.; Top, J.L.; Vorst, van der J.G.A.J.; Beulens, A.J.M.
2010-01-01
Food chain management research can help in the analysis and redesign of value creation and the product flow throughout the chain from primary producer down to the consumer. The aim is to meet consumer and societal requirements effectively at minimal cost. In the Wageningen UR strategic research prog
Modeling the effects of pharmaceutical marketing
Leeflang, P.S.H.; Wieringa, J.E.
Successful innovation of prescription drugs requires a substantial amount of marketing support. There is, however, much concern about the effects of marketing expenditures on the demand of pharmaceutical products (Manchanda et al., Market Lett 16(3/4):293-308, 2005). For example, excessive marketing
Modeling the effects of pharmaceutical marketing
Leeflang, P.S.H.; Wieringa, J.E.
2010-01-01
Successful innovation of prescription drugs requires a substantial amount of marketing support. There is, however, much concern about the effects of marketing expenditures on the demand of pharmaceutical products (Manchanda et al., Market Lett 16(3/4):293-308, 2005). For example, excessive marketing
Multivariate Term Structure Models with Level and Heteroskedasticity Effects
DEFF Research Database (Denmark)
Christiansen, Charlotte
2005-01-01
The paper introduces and estimates a multivariate level-GARCH model for the long rate and the term-structure spread where the conditional volatility is proportional to the ãth power of the variable itself (level effects) and the conditional covariance matrix evolves according to a multivariate GA...... and the level model. GARCH effects are more important than level effects. The results are robust to the maturity of the interest rates. Udgivelsesdato: MAY...
Modeling the effects of physician emigration on human development.
2011-01-01
We analyzed the effects of physician emigration on human development indicators in developing countries. First, the geographical distribution of physician brain drain was documented for the period 1991–2004. Second, random and fixed effects models were employed to investigate the effects of physicians in the home countries and abroad on child mortality and vaccination rates. Third, models were estimated to investigate migration-induced incentives in the medical sector that would increase the ...
Model Equations of Shape Memory Effect - Nitinol
Directory of Open Access Journals (Sweden)
Ion Vela
2010-01-01
Full Text Available Even it has been already confirmed that SMA’s have high potential for robotic actuators, actuators included in space robotics, underwater robotics, robotics for logistics, safety, as well as “green robotics” (robotics for the environment, energy conservation, sustainable development or agriculture, the number of applications of SMA-based actuators is still quite small, especially in applications in which their large strains, high specific work output and structural integration potential are useful,. The paper presents a formulated mathematical model calculated for binary SMA (Ni-Ti, helpful to estimate the stress distribution along with the transformation ratio of a SMA active element.
Clustering Effects Within the Dinuclear Model
Adamian, Gurgen; Antonenko, Nikolai; Scheid, Werner
The clustering of two nuclei in a nuclear system creates configurations denoted in literature as nuclear molecular structures. A nuclear molecule or a dinuclear system (DNS) as named by Volkov consists of two touching nuclei (clusters) which keep their individuality. Such a system has two main degrees of freedom of collective motions which govern its dynamics: (i) the relative motion between the clusters leading to molecular resonances in the internuclear potential and to the decay of the dinuclear system (separation of the clusters) which is called quasifission since no compound system like in fission is first formed. (ii) the transfer of nucleons or light constituents between the two clusters of the dinuclear system leading to a special dynamics of the mass and charge asymmetries between the clusters in fusion and fission reactions. In this article we discuss the essential aspects of the diabatic internuclear potential used by the di-nuclear system concept and present applications to nuclear structure and reactions. We show applications of the dinuclear model to superdeformed and hyperdeformed bands. An extended discussion is given to the problems of fusion dynamics in the production of superheavy nuclei, to the quasifission process and to multi-nucleon transfer between nuclei. Also the binary and ternary fission processes are discussed within the scission-point model and the dinuclear system concept.
Antenna model of the Purcell effect
Krasnok, Alexander E; Simovski, Constantin R; Tretyakov, Sergei A; Poddubny, Alexander N; Miroshnichenko, Andrey E; Kivshar, Yuri S; Belov, Pavel A
2015-01-01
The Purcell effect - the modification of the spontaneous emission rate in presence of resonant cavities or other resonant objects - is a fundamental effect of quantum electrodynamics. However, a change of the emission rate caused by environment different from free space has a classical counterpart. Not only quantum emitters, but any small antenna tuned to the resonance is an oscillator with radiative losses, and the influence of the environment on its radiation can be understood and measured in terms of the antenna radiation resistance. We present a general approach which is applicable to measurements of the Purcell factor for radio antennas and to calculations of these factors for quantum emitters. Our methodology is suitable for calculation and measurement of both electric and magnetic Purcell factors, it is versatile and applies to various frequency ranges. The approach is illustrated by a general equivalent scheme and allows the Purcell factor to be expressed through the continious radiation of a small an...
Modeling the ocean effect of geomagnetic storms
DEFF Research Database (Denmark)
Olsen, Nils; Kuvshinov, A.
2004-01-01
At coastal sites, geomagnetic variations for periods shorter than a few days are strongly distorted by the conductivity of the nearby sea-water. This phenomena, known as the ocean (or coast) effect, is strongest in the magnetic vertical component. We demonstrate the ability to predict the ocean...... if the oceans are considered. Our analysis also indicates a significant local time asymmetry (i.e., contributions from spherical harmonics other than P-I(0)), especially during the main phase of the storm....
Effective models for interacting quarks from QCD
Energy Technology Data Exchange (ETDEWEB)
Braghin, Fabio L. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Fisica
2012-07-01
Full text: In this work the Quantum Chromodynamics ( QCD ) path integral is considered with the introduction of auxiliary variables for composite gluon fields. One of these variables eventually leads to the gluon condensates of order 2 and another one corresponds to an anti - symmetric composite gluon configuration. Gluon degrees of freedom, and part of the quark degrees of freedom, are integrated out and two different limits of the resulting effective quark interactions are analysed. (author)
An effective model for dynamic finite difference calculations
Energy Technology Data Exchange (ETDEWEB)
Dey, T.N.
1996-01-01
An effective stress model, which simulates the mechanical effects of pore fluids on deformation and strength of porous materials, is described. The model can directly use SESAME table equations-of-state (EOSs) for the solid and fluid components. the model assumes that undrained (no fluid flow) conditions occur. Elastic and crushing behavior of the pore space can be specified from the results of simple laboratory tests. The model fully couples deviatoric and volumetric behavior in the sense that deviatoric and tensile failure depend on the effective pressure, while volumetric changes caused by deviatoric failure are coupled back to the volumetric behavior of the material. Strain hardening and softening of the yield surface, together with a number of flow rules, can be modeled. This model has been implemented into the SMC123 and CTH codes.
Effective UV radiation from model calculations and measurements
Feister, Uwe; Grewe, Rolf
1994-01-01
Model calculations have been made to simulate the effect of atmospheric ozone and geographical as well as meteorological parameters on solar UV radiation reaching the ground. Total ozone values as measured by Dobson spectrophotometer and Brewer spectrometer as well as turbidity were used as input to the model calculation. The performance of the model was tested by spectroradiometric measurements of solar global UV radiation at Potsdam. There are small differences that can be explained by the uncertainty of the measurements, by the uncertainty of input data to the model and by the uncertainty of the radiative transfer algorithms of the model itself. Some effects of solar radiation to the biosphere and to air chemistry are discussed. Model calculations and spectroradiometric measurements can be used to study variations of the effective radiation in space in space time. The comparability of action spectra and their uncertainties are also addressed.
Two-dimensional effects in nonlinear Kronig-Penney models
DEFF Research Database (Denmark)
Gaididei, Yuri Borisovich; Christiansen, Peter Leth; Rasmussen, Kim
1997-01-01
An analysis of two-dimensional (2D) effects in the nonlinear Kronig-Penney model is presented. We establish an effective one-dimensional description of the 2D effects, resulting in a set of pseudodifferential equations. The stationary states of the 2D system and their stability is studied...
Cellular automaton model considering headway-distance effect
Institute of Scientific and Technical Information of China (English)
Hu Shou-Xin; Gao Kun; Wang Bing-Hong; Lu Yu-Feng
2008-01-01
This paper presents a cellular automaton model for single-lane traffic flow.On the basis of the Nagel-Schreckenberg (NS) model,it further considers the effect of headway-distance between two successive cars on the randomization of the latter one.In numerical simulations,this model shows the following characteristics.(1) With a simple structure,this model succeeds in reproducing the hysteresis effect,which is absent in the NS model.(2) Compared with the slow-tostart models,this model exhibits a local fundamental diagram which is more consistent to empirical observations.(3)This model has much higher efficiency in dissolving congestions compared with the so-called NS model with velocitydependent randomization (VDR model).(4) This model is more robust when facing traffic obstructions.It can resist much longer shock times and has much shorter relaxation times on the other hand.To summarize,compared with the existing models,this model is quite simple in structure,but has good characteristics.
Opinion dynamics: models, extensions and external effects
Sîrbu, Alina; Servedio, Vito D P; Tria, Francesca
2016-01-01
Recently, social phenomena have received a lot of attention not only from social scientists, but also from physicists, mathematicians and computer scientists, in the emerging interdisciplinary field of complex system science. Opinion dynamics is one of the processes studied, since opinions are the drivers of human behaviour, and play a crucial role in many global challenges that our complex world and societies are facing: global financial crises, global pandemics, growth of cities, urbanisation and migration patterns, and last but not least important, climate change and environmental sustainability and protection. Opinion formation is a complex process affected by the interplay of different elements, including the individual predisposition, the influence of positive and negative peer interaction (social networks playing a crucial role in this respect), the information each individual is exposed to, and many others. Several models inspired from those in use in physics have been developed to encompass many of t...
Modeling of Dissolution Effects on Waterflooding
DEFF Research Database (Denmark)
Alexeev, Artem; Shapiro, Alexander; Thomsen, Kaj
2015-01-01
Physico-chemical interactions between the fluid and reservoir rock due to the presence of active components in the injected brine produce changes within the reservoir and can significantly impact the fluid flow. We have developed a 1D numerical model for waterflooding accounting for dissolution...... and precipitation of the components. Extending previous studies, we consider an arbitrary chemical non-equilibrium reaction-induced dissolution. We account for different individual volumes that a component has when precipitated or dissolved. This volume non-additivity also affects the pressure and the flow rate...... reaction rates) may exhibit rapid increase of porosity and permeability near the inlet probably indicating a formation of high permeable channels (wormholes). Water saturation in the zone of dissolution increases due to an increase in the bulk volume accessible for the injected fluid. Volumetric non...
Modeling Temporal Behavior of Awards Effect on Viewership of Movies
Altaf, Basmah
2017-04-22
The “rich get richer” effect is well-known in recommendation system. Popular items are recommended more, then purchased more, resulting in becoming even more popular over time. For example, we observe in Netflix data that awarded movies are more popular than non-awarded movies. Unlike other work focusing on making fair/neutralized recommendation, in this paper, we target on modeling the effect of awards on the viewership of movies. The main challenge of building such a model is that the effect on popularity changes over time with different intensity from movie to movie. Our proposed approach explicitly models the award effects for each movie and enables the recommendation system to provide a better ranked list of recommended movies. The results of an extensive empirical validation on Netflix and MovieLens data demonstrate the effectiveness of our model.
A Normative Model of Work Team Effectiveness
1983-11-01
contexts--an emphasis also seen in man’.’ state-of-the-art action projects invo)ving ,ork teams in orc~anizataons (e.g., Foza & Varkus, 1%O) The Role ...1976. Belbin , R. M. Manage’-ent teams : Wh’y the," suzceed or fail. London Hene! ann, 193’. Bertcher, H. J. & Maple, F. F. Creating orcups. Beverly...J. j. The role of team development in organizational effectiveness: A critical review. Psychological Bulletin, 1930, 88, 166-186. Zander, A
The multilevel p2 model : A random effects model for the analysis of multiple social networks
Zijlstra, B.J.H.; van Duijn, M.A.J.; Snijders, T.A.B.
2006-01-01
The p2 model is a random effects model with covariates for the analysis of binary directed social network data coming from a single observation of a social network. Here, a multilevel variant of the p2 model is proposed for the case of multiple observations of social networks, for example, in a samp
Fan, Xitao; Wang, Lin; Thompson, Bruce
1999-01-01
A Monte Carlo simulation study investigated the effects on 10 structural equation modeling fit indexes of sample size, estimation method, and model specification. Some fit indexes did not appear to be comparable, and it was apparent that estimation method strongly influenced almost all fit indexes examined, especially for misspecified models. (SLD)
Modeling individual effects in the Cormack-Jolly-Seber Model: A state-space formulation
Royle, J. Andrew
2008-01-01
In population and evolutionary biology, there exists considerable interest in individual heterogeneity in parameters of demographic models for open populations. However, flexible and practical solutions to the development of such models have proven to be elusive. In this article, I provide a state-space formulation of open population capture-recapture models with individual effects. The state-space formulation provides a generic and flexible framework for modeling and inference in models with individual effects, and it yields a practical means of estimation in these complex problems via contemporary methods of Markov chain Monte Carlo. A straightforward implementation can be achieved in the software package WinBUGS. I provide an analysis of a simple model with constant parameter detection and survival probability parameters. A second example is based on data from a 7-year study of European dippers, in which a model with year and individual effects is fitted.
The Development of Hierarchy of Effects Model in Advertising
Directory of Open Access Journals (Sweden)
Bambang Sukma Wijaya
2012-04-01
Full Text Available This paper aims to review the hierarchy of effects models in adverti-sing, especially the well-known model, AIDA (Attention, Interest, De-sire, and Action. Since its introduction by Lewis (1900 and generally attributed in the marketing and advertising literature by Strong (1925, the concept of AIDA’s hierarchy of effects model has been used by many researchers, both academicians and practitioners. The model is used to measure the effect of an advertisement. However, the deve-lopment of information technology has radically changed the way of how people communicate and socialize; as well as a paradigm shift from product-oriented marketing to consumer-oriented marketing or people-oriented marketing. Therefore, the variables in the hierarchy of effects model needs to be updated in respond to the latest develop-ments in the notice of public power as consumer audience. Based on deep literature review and reflective method, this paper introduces a new developed concept of hierarchy of effects model that was adop-ted from AIDA’s hierarchy of effects model, namely: AISDALSLove (At-tention, Interest, Search, Desire, Action, Like/dislike, Share, and Love/hate.
Efficient anisotropic wavefield extrapolation using effective isotropic models
Alkhalifah, Tariq Ali
2013-06-10
Isotropic wavefield extrapolation is more efficient than anisotropic extrapolation, and this is especially true when the anisotropy of the medium is tilted (from the vertical). We use the kinematics of the wavefield, appropriately represented in the high-frequency asymptotic approximation by the eikonal equation, to develop effective isotropic models, which are used to efficiently and approximately extrapolate anisotropic wavefields using the isotropic, relatively cheaper, operators. These effective velocity models are source dependent and tend to embed the anisotropy in the inhomogeneity. Though this isotropically generated wavefield theoretically shares the same kinematic behavior as that of the first arrival anisotropic wavefield, it also has the ability to include all the arrivals resulting from a complex wavefield propagation. In fact, the effective models reduce to the original isotropic model in the limit of isotropy, and thus, the difference between the effective model and, for example, the vertical velocity depends on the strength of anisotropy. For reverse time migration (RTM), effective models are developed for the source and receiver fields by computing the traveltime for a plane wave source stretching along our source and receiver lines in a delayed shot migration implementation. Applications to the BP TTI model demonstrates the effectiveness of the approach.
Modeling the effects of annual influenza vaccination
Energy Technology Data Exchange (ETDEWEB)
Smith, D.J.; Ackley, D.H.; Forrest, S. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Computer Science; Perelson, A.S. [Los Alamos National Lab., NM (United States). Theoretical Div.
1998-12-31
Although influenza vaccine efficacy is 70--90% in young healthy first-time vaccinees, the efficacy in repeat vaccinees has varied considerably. In some studies, vaccine efficacy in repeat vaccinees was higher than in first-time vaccinees, whereas in other studies vaccine efficacy in repeat vaccinees was significantly lower than in first-time vaccinees and sometimes no higher than in unvaccinated controls. It is known that the closeness of the antigenic match between the vaccine strain and the epidemic virus is important for vaccine effectiveness. In this study the authors show that the antigenic differences between a first vaccine strain and a second vaccine strain, and between the first vaccine strain and the epidemic strain, might account for the observed variation in attack rate among two-time vaccinees.
Gompertzian stochastic model with delay effect to cervical cancer growth
Energy Technology Data Exchange (ETDEWEB)
Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor and UTM Centre for Industrial and Applied Mathematics (UTM-CIAM), Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)
2015-02-03
In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.
Gompertzian stochastic model with delay effect to cervical cancer growth
Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti; Bahar, Arifah
2015-02-01
In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.
Modeling the isotope effect in Walden inversion reactions
Schechter, Israel
1991-05-01
A simple model to explain the isotope effect in the Walden exchange reaction is suggested. It is developed in the spirit of the line-of-centers models, and considers a hard-sphere collision that transfers energy from the relative translation to the desired vibrational mode, as well as geometrical properties and steric requirements. This model reproduces the recently measured cross sections for the reactions of hydrogen with isotopic silanes and older measurements of the substitution reactions of tritium atoms with isotopic methanes. Unlike previously given explanations, this model explains the effect of the attacking atom as well as of the other participating atoms. The model provides also qualitative explanation of the measured relative yields and thresholds of CH 3T and CH 2TF from the reaction T + CH 3F. Predictions for isotope effects and cross sections of some unmeasured reactions are given.
Bayesian nonparametric centered random effects models with variable selection.
Yang, Mingan
2013-03-01
In a linear mixed effects model, it is common practice to assume that the random effects follow a parametric distribution such as a normal distribution with mean zero. However, in the case of variable selection, substantial violation of the normality assumption can potentially impact the subset selection and result in poor interpretation and even incorrect results. In nonparametric random effects models, the random effects generally have a nonzero mean, which causes an identifiability problem for the fixed effects that are paired with the random effects. In this article, we focus on a Bayesian method for variable selection. We characterize the subject-specific random effects nonparametrically with a Dirichlet process and resolve the bias simultaneously. In particular, we propose flexible modeling of the conditional distribution of the random effects with changes across the predictor space. The approach is implemented using a stochastic search Gibbs sampler to identify subsets of fixed effects and random effects to be included in the model. Simulations are provided to evaluate and compare the performance of our approach to the existing ones. We then apply the new approach to a real data example, cross-country and interlaboratory rodent uterotrophic bioassay.
Organizational effectiveness: toward an integrated model for schools of nursing.
Baker, C M; Reising, D L; Johnson, D R; Stewart, R L; Baker, S D
1997-01-01
Assessing the quality of academic institutions involves much more than the opinions of peers or experts. Examination of the organizational effectiveness of schools of nursing has been neglected. Current emphasis on assessing educational outcomes has diverted attention from the construct, organizational effectiveness, and more comprehensive theory-driven approaches to evaluation. This review of the organizational effectiveness literature focuses on the major assessment models: goal attainment, human relations, open systems, internal processes, culture, and life cycle. Attention is given to the influence of organizational maturation on an integrated model of organizational effectiveness. Selected macrolevel studies of schools of nursing are examined, and an agenda for nursing research is proposed.
Intelligence and Birth Order among Children and Adolescents in Psychiatric Care
Kirkcaldy, Bruce; Furnham, Adrian; Siefen, Georg
2009-01-01
A sample of around 2,500 adolescents in a child and adolescent psychiatry clinic in the region of Munster, Germany had their intelligence assessed. Family size (total number of siblings within a family) was significantly correlated with intelligence score categories (-0.08 and -0.19 for males and females). First borns and only children displayed…
Cohort birth order, parity progression ratio and parity distribution trends in developed countries
Directory of Open Access Journals (Sweden)
Jean-Paul Sardon
2007-04-01
Full Text Available Major changes in childbearing patterns are continuously taking place in the majority of low-fertility populations with postponement being virtually universal. Almost everywhere the two-child family became dominant. Proportions of childless women and one-child families were increasing recently. Changes in childbearing patterns in Central and Eastern Europe have been profound justifying the label of an historic transformation. Young women are bearing considerably fewer children compared to older cohorts. Especially proportions of women having second births in most CEE countries were declining rapidly and these were lower than in western countries. Postponement of childbearing might be nearing cessation in some western countries.
Effect of Xanthone Derivatives on Animal Models of Depression
Directory of Open Access Journals (Sweden)
Xu Zhao, MD
2014-12-01
Conclusions: Within certain dose ranges, xanthone derivatives 1101 and 1105 have similar effects to venlafaxine hydrochloride in the treatment of depression as suggested by behavioral despair animal models using rats and mice.
Multilevel random effect and marginal models for longitudinal data ...
African Journals Online (AJOL)
Multilevel random effect and marginal models for longitudinal data. ... Ethiopian Journal of Science and Technology ... the occurrence of specific adverse events than children injected with licensed vaccine, and if so, to quantify the difference.
Enhancing treatment effectiveness through social modelling: A pilot study.
Faasse, Kate; Perera, Anna; Loveys, Kate; Grey, Andrew; Petrie, Keith J
2017-05-01
Medical treatments take place in social contexts; however, little research has investigated how social modelling might influence treatment outcomes. This experimental pilot study investigated social modelling of treatment effectiveness and placebo treatment outcomes. Fifty-nine participants took part in the study, ostensibly examining the use of beta-blockers (actually placebos) for examination anxiety. Participants were randomly assigned to observe a female confederate report positive treatment effects (reduced heart rate, relaxed, calm) or feeling no different. Heart rate, anxiety and blood pressure were assessed, as were symptoms and attributed side effects. Heart rate decreased significantly more in the social modelling compared to control condition, p = .027 (d = .63), and there were trends towards effects in the same direction for both anxiety, p = .097 (d = .46), and systolic blood pressure, p = .077 (d = .51). Significant pre-post placebo differences in heart rate, anxiety and diastolic blood pressure were found in the social modelling group, ps .28 (ds = .09-.59). Social observation of medication effectiveness enhanced placebo effectiveness in heart rate, and showed a trend towards enhancing treatment effectiveness in both anxiety and systolic blood pressure. Social modelling may have utility in enhancing the effectiveness of many active medical treatments.
Adapting Axelrod's cultural dissemination model for simulating peer effects.
Hofer, Christian; Lechner, Gernot; Brudermann, Thomas; Füllsack, Manfred
2017-01-01
We present a generic method for considering incomplete but gradually expandable sociological data in agent-based modeling based on the classic model of cultural dissemination by Axelrod. Our method extension was inspired by research on the diffusion of citizen photovoltaic initiatives, i.e. by initiatives in which citizens collectively invest in photovoltaic plants and share the profits. Owing to the absence of empirical interaction parameters, the Axelrod model was used as basis for considering peer effects with contrived interaction data that can be updated from empirical surveys later on. The Axelrod model was extended to cover the following additional features: •Consideration of empirical social science data for concrete social interaction.•Development of a variable and fine-tunable interaction function for agents.•Deployment of a generic procedure for modeling peer effects in agent-based models.
DEFF Research Database (Denmark)
Olesen, H. R.; Løfstrøm, P.; Berkowicz, R.;
dispersion models for estimating local concentration levels in general. However, the report focuses on some particular issues, which are relevant for subsequent work on odour due to animal production. An issue of primary concern is the effect that buildings (stables) have on flow and dispersion. The handling...... of building effects is a complicated problem, and a major part of the report is devoted to the treatment of building effects in dispersion models...
Hot Strange Hadronic Matter in an Effective Model
Institute of Scientific and Technical Information of China (English)
QIANWei-Liang; SURu-Keng; SONGHong-Qiu
2003-01-01
An effective model used to describe the strange hadronic matter with nucleons, A-hyperons, and [I]-hyperons is extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fraction dependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy and pressure, as well as the equation of state of the matter, are given.
A FIBER-BRIDGING MODEL WITH STRESS GRADIENT EFFECTS
Institute of Scientific and Technical Information of China (English)
孙毅; 李涛
2000-01-01
Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China)ABSTRACT: A fiber-bridging model with stress gradient effects is proposed for unidirectional fiber-reinforced composites. The stress gradient terms are introduced by solving a micromechanical model under a non-uniform stress loading. It is shown that the stress gradient effect is significant on both the fiber-bridging stress distribution and the value of the critical load of fiber failure.
Effectiveness of Two Water Conservation Policies: An Integrated Modeling Approach
Das, Biswa R.; Willis, David B.; Johnson, Jeffrey W.
2010-01-01
Agriculture in the Texas High Plains depends entirely on the Ogallala Aquifer. Texas enacted water conservation legislation to address declining reserves in the aquifer. We developed an integrated regional water policy model that links a hydrology model with an economic optimization model to estimate policy impacts with respect to economic cost and water conservation. Testing the effectiveness of two policies, a groundwater extraction tax and extraction quotas, we observe that neither signifi...
Effectiveness of Two Water Conservation Policies: An Integrated Modeling Approach
Das, Biswa R.; Willis, David B.; Johnson, Jeffrey W.
2010-01-01
Agriculture in the Texas High Plains depends entirely on the Ogallala Aquifer. Texas enacted water conservation legislation to address declining reserves in the aquifer. We developed an integrated regional water policy model that links a hydrology model with an economic optimization model to estimate policy impacts with respect to economic cost and water conservation. Testing the effectiveness of two policies, a groundwater extraction tax and extraction quotas, we observe that neither signifi...
INFLUENCE ANALYSIS ON EXPONENTIAL NONLINEAR MODELS WITH RANDOM EFFECTS
Institute of Scientific and Technical Information of China (English)
宗序平; 赵俊; 王海斌; 韦博成
2003-01-01
This paper presents a unified diagnostic method for exponential nonlinear models with random effects based upon the joint likelihood given by Robinson in 1991.The authors show that the case deletion model is equivalent to mean shift outlier model.From this point of view,several diagnostic measures,such as Cook distance,score statistics are derived.The local influence measure of Cook is also presented.Numerical example illustrates that our method is available.
INFLUENCE ANALYSIS IN NONLINEAR MODELS WITH RANDOM EFFECTS
Institute of Scientific and Technical Information of China (English)
WeiBocheng; ZhongXuping
2001-01-01
Abstract. In this paper,a unified diagnostic method for the nonlinear models with random ef-fects based upon the joint likelihood given by Robinson in 1991 is presented. It is shown that thecase deletion model is equivalent to the mean shift outlier model. From this point of view ,sever-al diagnostic measures, such as Cook distance, score statistics are derived. The local influencemeasure of Cook is also presented. A numerical example illustrates that the method is avail-able
Little Higgs model effects in gg ® gg
Choudhury, S. Rai; Goyal, Ashok; Cornell, A. S.; Gaur, Naveen
2007-11-01
Though the predictions of the standard model (SM) are in excellent agreement with experiments, there are still several theoretical problems associated with the Higgs sector of the SM, where it is widely believed that some {new physics} will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we have investigated the effects of the LH model on gggg scattering [1].
Effects of tidal gravitational fields in clustering dark energy models
Pace, Francesco; Reischke, Robert; Meyer, Sven; Schäfer, Björn Malte
2017-04-01
We extend a previous work by Reischke et al. by studying the effects of tidal shear on clustering dark energy models within the framework of the extended spherical collapse model and using the Zel'dovich approximation. As in previous works on clustering dark energy, we assumed a vanishing effective sound speed describing the perturbations in dark energy models. To be self-consistent, our treatment is valid only on linear scales since we do not intend to introduce any heuristic models. This approach makes the linear overdensity δc mass dependent and similarly to the case of smooth dark energy, its effects are predominant at small masses and redshifts. Tidal shear has effects of the order of per cent or less, regardless of the model and preserves a well-known feature of clustering dark energy: When dark energy perturbations are included, the models resemble better the Lambda cold dark matter evolution of perturbations. We also showed that effects on the comoving number density of haloes are small and qualitatively and quantitatively in agreement with what were previously found for smooth dark energy models.
Modeling Dynamic Effects of the Marketing Mix on Market Shares
D. Fok (Dennis); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)
2003-01-01
textabstractTo comprehend the competitive structure of a market, it is important to understand the short-run and long-run effects of the marketing mix on market shares. A useful model to link market shares with marketing-mix variables, like price and promotion, is the market share attraction model.
Estimation of Spatial Dynamic Nonparametric Durbin Models with Fixed Effects
Qian, Minghui; Hu, Ridong; Chen, Jianwei
2016-01-01
Spatial panel data models have been widely studied and applied in both scientific and social science disciplines, especially in the analysis of spatial influence. In this paper, we consider the spatial dynamic nonparametric Durbin model (SDNDM) with fixed effects, which takes the nonlinear factors into account base on the spatial dynamic panel…
Modeling the Effect of Oil Price on Global Fertilizer Prices
P-Y. Chen (Ping-Yu); C-L. Chang (Chia-Lin); C-C. Chen (Chi-Chung); M.J. McAleer (Michael)
2010-01-01
textabstractThe main purpose of this paper is to evaluate the effect of crude oil price on global fertilizer prices in both the mean and volatility. The endogenous structural breakpoint unit root test, the autoregressive distributed lag (ARDL) model, and alternative volatility models, including the
Modeling Dynamic Effects of the Marketing Mix on Market Shares
D. Fok (Dennis); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)
2003-01-01
textabstractTo comprehend the competitive structure of a market, it is important to understand the short-run and long-run effects of the marketing mix on market shares. A useful model to link market shares with marketing-mix variables, like price and promotion, is the market share attraction model.
Effective poroelastic model for one-dimensional wave propagation
Kudarova, A.; Van Dalen, K.N.; Drijkoningen, G.G.
2013-01-01
An effective poroelastic model is proposed that describes seismic attenuation and dispersion in periodically layeredmedia. In this model, the layers represent mesoscopic-scale heterogeneities (larger than the grain and pore sizes but smaller than the wavelength) that can occur both in fluid and soli
Personal Coaching: Reflection on a Model for Effective Learning
Griffiths, Kerryn
2015-01-01
The article "Personal Coaching: A Model for Effective Learning" (Griffiths, 2006) appeared in the "Journal of Learning Design" Volume 1, Issue 2 in 2006. Almost ten years on, Kerryn Griffiths reflects upon her original article. Specifically, Griffiths looks back at the combined coaching-learning model she suggested in her…
Effects of Scenario Planning on Participant Mental Models
Glick, Margaret B.; Chermack, Thomas J.; Luckel, Henry; Gauck, Brian Q.
2012-01-01
Purpose: The purpose of this paper is to assess the effects of scenario planning on participant mental model styles. Design/methodology/approach: The scenario planning literature is consistent with claims that scenario planning can change individual mental models. These claims are supported by anecdotal evidence and stories from the practical…
Making Assessment Easier with the Organizational Effectiveness Model
Heilman, Savannah C.; Kennedy-Phillips, Lance
2011-01-01
The Organizational Effectiveness Model was originally developed by Lance Kennedy-Phillips and Ellen Meents-DeCaigny at DePaul University and has been adapted to address the needs of The Ohio State University. The model's purpose is to help organizations measure progress toward mission fulfillment and goal achievement. It cascades, with each step…
Making Assessment Easier with the Organizational Effectiveness Model
Heilman, Savannah C.; Kennedy-Phillips, Lance
2011-01-01
The Organizational Effectiveness Model was originally developed by Lance Kennedy-Phillips and Ellen Meents-DeCaigny at DePaul University and has been adapted to address the needs of The Ohio State University. The model's purpose is to help organizations measure progress toward mission fulfillment and goal achievement. It cascades, with each step…
Analysis of effect factors-based stochastic network planning model
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Looking at all the indeterminate factors as a whole and regarding activity durations as independent random variables,the traditional stochastic network planning models ignore the inevitable relationship and dependence among activity durations when more than one activity is possibly affected by the same indeterminate factors.On this basis of analysis of indeterminate effect factors of durations,the effect factors-based stochastic network planning (EFBSNP) model is proposed,which emphasizes on the effects of not only logistic and organizational relationships,but also the dependent relationships,due to indeterminate factors among activity durations on the project period.By virtue of indeterminate factor analysis the model extracts and describes the quantitatively indeterminate effect factors,and then takes into account the indeterminate factors effect schedule by using the Monte Carlo simulation technique.The method is flexible enough to deal with effect factors and is coincident with practice.A software has been developed to simplify the model-based calculation,in VisualStudio.NET language.Finally,a case study is included to demonstrate the applicability of the proposed model and comparison is made with some advantages over the existing models.
Directory of Open Access Journals (Sweden)
Mehran FARAJOLLAHI
2010-07-01
Full Text Available The present research aims at presenting a conceptual model for effective distance learning in higher education. Findings of this research shows that an understanding of the technological capabilities and learning theories especially constructive theory and independent learning theory and communicative and interaction theory in Distance learning is an efficient factor in the planning of effective Distance learning in higher education. Considering the theoretical foundations of the present research, in the effective distance learning model, the learner is situated at the center of learning environment. For this purpose, the learner needs to be ready for successful learning and the teacher has to be ready to design the teaching- learning activities when they initially enter the environment. In the present model, group and individual active teaching-learning approach, timely feedback, using IT and eight types of interactions have been designed with respect to theoretical foundations and current university missions. From among the issues emphasized in this model, one can refer to the Initial, Formative and Summative evaluations. In an effective distance learning environment, evaluation should be part of the learning process and the feedback resulting from it should be used to improve learning. For validating the specified features, the opinions of Distance learning experts in Payame Noor, Shiraz, Science and Technology and Amirkabir Universities have been used which verified a high percentage of the statistical sample of the above mentioned features.
General Friction Model Extended by the Effect of Strain Hardening
DEFF Research Database (Denmark)
Nielsen, Chris V.; Martins, Paulo A.F.; Bay, Niels
2016-01-01
An extension to the general friction model proposed by Wanheim and Bay [1] to include the effect of strain hardening is proposed. The friction model relates the friction stress to the fraction of real contact area by a friction factor under steady state sliding. The original model for the real co...... of friction in metal forming, where the material generally strain hardens. The extension of the model to cover strain hardening materials is validated by comparison to previously published experimental data.......An extension to the general friction model proposed by Wanheim and Bay [1] to include the effect of strain hardening is proposed. The friction model relates the friction stress to the fraction of real contact area by a friction factor under steady state sliding. The original model for the real......-ideally plastic material, and secondly, to extend the solution by the influence of material strain hardening. This corresponds to adding a new variable and, therefore, a new axis to the general friction model. The resulting model is presented in a combined function suitable for e.g. finite element modeling...
A Bayesian Network View on Nested Effects Models
Directory of Open Access Journals (Sweden)
Fröhlich Holger
2009-01-01
Full Text Available Nested effects models (NEMs are a class of probabilistic models that were designed to reconstruct a hidden signalling structure from a large set of observable effects caused by active interventions into the signalling pathway. We give a more flexible formulation of NEMs in the language of Bayesian networks. Our framework constitutes a natural generalization of the original NEM model, since it explicitly states the assumptions that are tacitly underlying the original version. Our approach gives rise to new learning methods for NEMs, which have been implemented in the /Bioconductor package nem. We validate these methods in a simulation study and apply them to a synthetic lethality dataset in yeast.
Pion Effect of Nuclear Matter in a Chiral Sigma Model
Institute of Scientific and Technical Information of China (English)
HU Jin-niu; Y.Ogawa; H.Toki; A.Hosaka; SHEN Hong
2009-01-01
We develop a new framework for the study of the nuclear matter based on the linear sigma model.We introduce a completely new viewpoint on the treatment of the nuclear matter with the inclusion of the pion.We extend the relativistic chiral mean field model by using the similar method in the tensor optimized shell model.We also regulate the pion-nucleon interaction by considering the form-factor and short range repulsion effects.We obtain the equation of state of nuclear matter and study the importance of the pion effect.
Modeling of dynamic effects of a low power laser beam
Lawrence, George N.; Scholl, Marija S.; Khatib, AL
1988-01-01
Methods of modeling some of the dynamic effects involved in laser beam propagation through the atmosphere are addressed with emphasis on the development of simple but accurate models which are readily implemented in a physical optics code. A space relay system with a ground based laser facility is considered as an example. The modeling of such characteristic phenomena as laser output distribution, flat and curved mirrors, diffraction propagation, atmospheric effects (aberration and wind shear), adaptive mirrors, jitter, and time integration of power on target, is discussed.
Measuring the neighbourhood effect to calibrate land use models
Vliet, van J.; Naus, N.; Lammeren, van R.J.A.; Bregt, A.K.; Hurkens, J.; Delden, van H.
2013-01-01
Many spatially explicit land use models include the neighbourhood effect as a driver of land use changes. The neighbourhood effect includes the inertia of land uses over time, the conversion from one land use to another, and the attraction or repulsion of surrounding land uses. The neighbourhood eff
Properties of Strange Matter in a Model with Effective Lagrangian
Institute of Scientific and Technical Information of China (English)
WANG Ping; SU Ru-Keng; SONG Hong-Qiu; ZHANG Li-Liang
2001-01-01
The strange hadronic matter with nucleons, A-hyperons and E-hyperons is studied by using an effective nuclear model in a mean-field approximation. The density and strangeness fraction dependence of the effective baryon masses as well as the saturation properties and stabilities of the strange hadronic matter are discussed.``
Effects of Role Models and Gender on Students’ Entrepreneurial Intentions
Karimi, S.; Biemans, H.J.A.; Lans, T.; Chizari, M.; Mulder, M.
2014-01-01
Purpose – This paper aims to, drawing on the theory of planned behaviour (TPB), explore the effects of entrepreneurial role models on entrepreneurial intention (EI) and its antecedents and examines the question of whether the effects vary by gender. Design/methodology/approach – Data were collected
A hierarchical Bayes error correction model to explain dynamic effects
D. Fok (Dennis); C. Horváth (Csilla); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)
2004-01-01
textabstractFor promotional planning and market segmentation it is important to understand the short-run and long-run effects of the marketing mix on category and brand sales. In this paper we put forward a sales response model to explain the differences in short-run and long-run effects of promotio
School Processes Mediate School Compositional Effects: Model Specification and Estimation
Liu, Hongqiang; Van Damme, Jan; Gielen, Sarah; Van Den Noortgate, Wim
2015-01-01
School composition effects have been consistently verified, but few studies ever attempted to study how school composition affects school achievement. Based on prior research findings, we employed multilevel mediation modeling to examine whether school processes mediate the effect of school composition upon school outcomes based on the data of 28…
New Calculations in Dirac Gaugino Models: Operators, Expansions, and Effects
Carpenter, Linda M
2015-01-01
In this work we calculate important one loop SUSY-breaking parameters in models with Dirac gauginos, which are implied by the existence of heavy messenger fields. We find that these SUSY-breaking effects are all related by a small number of parameters, thus the general theory is tightly predictive. In order to make the most accurate analyses of one loop effects, we introduce calculations using an expansion in SUSY breaking messenger mass, rather than relying on postulating the forms of effective operators. We use this expansion to calculate one loop contributions to gaugino masses, non-holomorphic SM adjoint masses, new A-like and B-like terms, and linear terms. We also test the Higgs potential in such models, and calculate one loop contributions to the Higgs mass in certain limits of R-symmetric models, finding a very large contribution in many regions of the $\\mu$-less MSSM, where Higgs fields couple to standard model adjoint fields.
Effective action and semiclassical limit of spin foam models
Mikovic, A
2011-01-01
We define an effective action for spin foam models of quantum gravity by adapting the background field method from quantum field theory. We show that the Regge action is the leading term in the semi-classical expansion of the spin foam effective action if the vertex amplitude has the large-spin asymptotics which is proportional to an exponential function of the vertex Regge action. In the case of the known three-dimensional and four-dimensional spin foam models this amounts to modifying the vertex amplitude such that the exponential asymptotics is obtained. In particular, we show that the ELPR/FK model vertex amplitude can be modified such that the new model is finite and has the Einstein-Hilbert action as its classical limit. We also calculate the first-order and some of the second-order quantum corrections in the semi-classical expansion of the effective action.
A Layered Decision Model for Cost-Effective System Security
Energy Technology Data Exchange (ETDEWEB)
Wei, Huaqiang; Alves-Foss, James; Soule, Terry; Pforsich, Hugh; Zhang, Du; Frincke, Deborah A.
2008-10-01
System security involves decisions in at least three areas: identification of well-defined security policies, selection of cost-effective defence strategies, and implementation of real-time defence tactics. Although choices made in each of these areas affect the others, existing decision models typically handle these three decision areas in isolation. There is no comprehensive tool that can integrate them to provide a single efficient model for safeguarding a network. In addition, there is no clear way to determine which particular combinations of defence decisions result in cost-effective solutions. To address these problems, this paper introduces a Layered Decision Model (LDM) for use in deciding how to address defence decisions based on their cost-effectiveness. To validate the LDM and illustrate how it is used, we used simulation to test model rationality and applied the LDM to the design of system security for an e-commercial business case.
Numerical Modeling of Electromagnetic Field Effects on the Human Body
Directory of Open Access Journals (Sweden)
Zuzana Psenakova
2006-01-01
Full Text Available Interactions of electromagnetic field (EMF with environment and with tissue of human beings are still under discussion and many research teams are investigating it. The human simulation models are used for biomedical research in a lot of areas, where it is advantage to replace real human body (tissue by the numerical model. Biological effects of EMF are one of the areas, where numerical models are used with many advantages. On the other side, this research is very specific and it is always quite hard to simulate realistic human tissue. This paper deals with different possibilities of numerical modelling of electromagnetic field effects on the human body (especially calculation of the specific absorption rate (SAR distribution in human body and thermal effect.
Probability-summation model of multiple laser-exposure effects.
Menendez, A R; Cheney, F E; Zuclich, J A; Crump, P
1993-11-01
A probability-summation model is introduced to provide quantitative criteria for discriminating independent from interactive effects of multiple laser exposures on biological tissue. Data that differ statistically from predictions of the probability-summation model indicate the action of sensitizing (synergistic/positive) or desensitizing (hardening/negative) biophysical interactions. Interactions are indicated when response probabilities vary with changes in the spatial or temporal separation of exposures. In the absence of interactions, probability-summation parsimoniously accounts for "cumulative" effects. Data analyzed using the probability-summation model show instances of both sensitization and desensitization of retinal tissue by laser exposures. Other results are shown to be consistent with probability-summation. The relevance of the probability-summation model to previous laser-bioeffects studies, models, and safety standards is discussed and an appeal is made for improved empirical estimates of response probabilities for single exposures.
Deformed Calogero-Sutherland model and fractional quantum Hall effect
Atai, Farrokh; Langmann, Edwin
2017-01-01
The deformed Calogero-Sutherland (CS) model is a quantum integrable system with arbitrary numbers of two types of particles and reducing to the standard CS model in special cases. We show that a known collective field description of the CS model, which is based on conformal field theory (CFT), is actually a collective field description of the deformed CS model. This provides a natural application of the deformed CS model in Wen's effective field theory of the fractional quantum Hall effect (FQHE), with the two kinds of particles corresponding to electrons and quasi-hole excitations. In particular, we use known mathematical results about super-Jack polynomials to obtain simple explicit formulas for the orthonormal CFT basis proposed by van Elburg and Schoutens in the context of the FQHE.
Dynamic Model of Linear Induction Motor Considering the End Effects
Directory of Open Access Journals (Sweden)
H. A. Hairik
2009-01-01
Full Text Available In this paper the dynamic behavior of linear induction motor is described by a mathematical model taking into account the end effects and the core losses. The need for such a model rises due to the complexity of linear induction motors electromagnetic field theory. The end affects by introducing speed dependent scale factor to the magnetizing inductance and series resistance in the d-axis equivalent circuit. Simulation results are presented to show the validity of the model during both no-load and sudden load change intervals. This model can also be used directly in simulation researches for linear induction motor vector control drive systems.
Modeling the population lens effect in thermal lens spectrometry.
Silva, J R; Malacarne, L C; Baesso, M L; Lima, S M; Andrade, L H C; Jacinto, C; Hehlen, M P; Astrath, N G C
2013-02-15
We report a theoretical model and experimental results for laser-induced lensing in solids. The model distinguishes and quantifies the contributions from population and thermal effects. Laser-induced lensing in ytterbium-doped fluorozirconate glass ZBLAN:Yb(3+) is measured, and the thermal and optical properties obtained from analyzing the data with the proposed model agree well with published values. Photothermal techniques are used extensively for the investigation of laser and laser-cooling materials, and the model developed here enables the interpretation of convoluted laser-induced lensing signals that have contributions from different sources.
Effective Actions of Matrix Models on Homogeneous Spaces
Imai, T; Takayama, Y; Tomino, D
2002-01-01
We evaluate the effective actions of supersymmetric matrix models on fuzzy S^2times S^2 up to the two loop level. Remarkably it turns out to be a consistent solution of IIB matrix model. Based on the power counting and SUSY cancellation arguments, we can identify the 't Hooft coupling and large N scaling behavior of the effective actions to all orders. In the large N limit, the quantum corrections survive except in 2 dimensional limits. They are O(N) and O(N^{4over 3}) for 4 and 6 dimensional spaces respectively. We argue that quantum effects single out 4 dimensionality of space-time.
Faraway, Julian J
2005-01-01
Linear models are central to the practice of statistics and form the foundation of a vast range of statistical methodologies. Julian J. Faraway''s critically acclaimed Linear Models with R examined regression and analysis of variance, demonstrated the different methods available, and showed in which situations each one applies. Following in those footsteps, Extending the Linear Model with R surveys the techniques that grow from the regression model, presenting three extensions to that framework: generalized linear models (GLMs), mixed effect models, and nonparametric regression models. The author''s treatment is thoroughly modern and covers topics that include GLM diagnostics, generalized linear mixed models, trees, and even the use of neural networks in statistics. To demonstrate the interplay of theory and practice, throughout the book the author weaves the use of the R software environment to analyze the data of real examples, providing all of the R commands necessary to reproduce the analyses. All of the ...
The effect of model errors in variational assimilation
Wergen, Werner
1992-08-01
A linearized, one-dimensional shallow water model is used to investigate the effect of model errors in four-dimensional variational assimilation. A suitable initialization scheme for variational assimilation is proposed. Introducing deliberate phase speed errors in the model, the results from variational assimilation are compared to standard analysis/forecast cycle experiments. While the latter draws to the data and reflects the model errors only in the datavoid areas, variational assimilation with the model used as strong constraint is shown to distribute the model errors over the entire analysis domain. The implications for verification and diagnostics are discussed. Temporal weighting of the observations can reduce the errors towards the end of the assimilation period, but may deteriorate the subsequent forecasts. An extension to variational assimilation is proposed, which seeks not only to determine the initial state from the observations but also some of the tunable parameters of the model. The potentional usefulness of this approach for parameterization studies and for a separation of forecast errors into model- and analysis errors is discussed. Finally, variational assimilations with the model used as weak constraint are presented. While showing a good performance in the assimilation, forecasts can suffer severely if the extra term in the equations up to which the model is enforced are unable to compensate for the real model error. In the discussion, an overall appraisal of both assimilation methods is given.
Consistency in Estimation and Model Selection of Dynamic Panel Data Models with Fixed Effects
Directory of Open Access Journals (Sweden)
Guangjie Li
2015-07-01
Full Text Available We examine the relationship between consistent parameter estimation and model selection for autoregressive panel data models with fixed effects. We find that the transformation of fixed effects proposed by Lancaster (2002 does not necessarily lead to consistent estimation of common parameters when some true exogenous regressors are excluded. We propose a data dependent way to specify the prior of the autoregressive coefficient and argue for comparing different model specifications before parameter estimation. Model selection properties of Bayes factors and Bayesian information criterion (BIC are investigated. When model uncertainty is substantial, we recommend the use of Bayesian Model Averaging to obtain point estimators with lower root mean squared errors (RMSE. We also study the implications of different levels of inclusion probabilities by simulations.
The linear-quadratic model is inappropriate to model high dose per fraction effects in radiosurgery.
Kirkpatrick, John P; Meyer, Jeffrey J; Marks, Lawrence B
2008-10-01
The linear-quadratic (LQ) model is widely used to model the effect of total dose and dose per fraction in conventionally fractionated radiotherapy. Much of the data used to generate the model are obtained in vitro at doses well below those used in radiosurgery. Clinically, the LQ model often underestimates tumor control observed at radiosurgical doses. The underlying mechanisms implied by the LQ model do not reflect the vascular and stromal damage produced at the high doses per fraction encountered in radiosurgery and ignore the impact of radioresistant subpopulations of cells. The appropriate modeling of both tumor control and normal tissue toxicity in radiosurgery requires the application of emerging understanding of molecular-, cellular-, and tissue-level effects of high-dose/fraction-ionizing radiation and the role of cancer stem cells.
Three-dimensional effects for radio frequency antenna modeling
Energy Technology Data Exchange (ETDEWEB)
Carter, M.D.; Batchelor, D.B.; Stallings, D.C.
1993-12-31
Electromagnetic field calculations for radio frequency (rf) antennas in two dimensions (2-D) neglect finite antenna length effects as well as the feeders leading to the main current strap. The 2-D calculations predict that the return currents in the sidewalls of the antenna structure depend strongly on the plasma parameters, but this prediction is suspect because of experimental evidence. To study the validity of the 2-D approximation, the Multiple Antenna Implementation System (MAntIS) has been used to perform three-dimensional (3-D) modeling of the power spectrum, plasma loading, and inductance for a relevant loop antenna design. Effects on antenna performance caused by feeders to the main current strap and conducting sidewalls are considered. The modeling shows that the feeders affect the launched power spectrum in an indirect way by forcing the driven rf current to return in the antenna structure rather than the plasma, as in the 2-D model. It has also been found that poloidal dependencies in the plasma impedance matrix can reduce the loading predicted from that predicted in the 2-D model. For some plasma parameters, the combined 3-D effects can lead to a reduction in the predicted loading by as much as a factor of 2 from that given by the 2-D model, even with end-effect corrections for the 2-D model.
Three-dimensional effects for radio frequency antenna modeling
Carter, M. D.; Batchelor, D. B.; Stallings, D. C.
1994-10-01
Electromagnetic field calculations for radio frequency (rf) antennas in two dimensions (2-D) neglect finite antenna length effects as well as the feeders leading to the main current strap. The 2-D calculations predict that the return currents in the sidewalls of the antenna structure depend strongly on the plasma parameters, but this prediction is suspect because of experimental evidence. To study the validity of the 2-D approximation, the Multiple Antenna Implementation System (MAntIS) has been used to perform three-dimensional (3-D) modeling of the power spectrum, plasma loading, and inductance for a relevant loop antenna design. Effects on antenna performance caused by feeders to the main current strap and conducting sidewalls are considered. The modeling shows that the feeders affect the launched power spectrum in an indirect way by forcing the driven rf current to return in the antenna structure rather than the plasma, as in the 2-D model. It has also been found that poloidal dependencies in the plasma impedance matrix can reduce the loading predicted from that predicted in the 2-D model. For some plasma parameters, the combined 3-D effects can lead to a reduction in the predicted loading by as much as a factor of 2 from that given by the 2-D model, even with end-effect corrections for the 2-D model.
Three-dimensional effects for radio frequency antenna modeling
Energy Technology Data Exchange (ETDEWEB)
Carter, M.D.; Batchelor, D.B.; Stallings, D.C. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37821-8071 (United States))
1994-10-15
Electromagnetic field calculations for radio frequency (rf) antennas in two dimensions (2-D) neglect finite antenna length effects as well as the feeders leading to the main current strap. The 2-D calculations predict that the return currents in the sidewalls of the antenna structure depend strongly on the plasma parameters, but this prediction is suspect because of experimental evidence. To study the validity of the 2-D approximation, the Multiple Antenna Implementation System (MAntIS) has been used to perform three-dimensional (3-D) modeling of the power spectrum, plasma loading, and inductance for a relevant loop antenna design. Effects on antenna performance caused by feeders to the main current strap and conducting sidewalls are considered. The modeling shows that the feeders affect the launched power spectrum in an indirect way by forcing the driven rf current to return in the antenna structure rather than the plasma, as in the 2-D model. It has also been found that poloidal dependencies in the plasma impedance matrix can reduce the loading predicted from that predicted in the 2-D model. For some plasma parameters, the combined 3-D effects can lead to a reduction in the predicted loading by as much as a factor of 2 from that given by the 2-D model, even with end-effect corrections for the 2-D model.
Effective Elliptic Models for Efficient Wavefield Extrapolation in Anisotropic Media
Waheed, Umair bin
2014-05-01
Wavefield extrapolation operator for elliptically anisotropic media offers significant cost reduction compared to that of transversely isotropic media (TI), especially when the medium exhibits tilt in the symmetry axis (TTI). However, elliptical anisotropy does not provide accurate focusing for TI media. Therefore, we develop effective elliptically anisotropic models that correctly capture the kinematic behavior of the TTI wavefield. Specifically, we use an iterative elliptically anisotropic eikonal solver that provides the accurate traveltimes for a TI model. The resultant coefficients of the elliptical eikonal provide the effective models. These effective models allow us to use the cheaper wavefield extrapolation operator for elliptic media to obtain approximate wavefield solutions for TTI media. Despite the fact that the effective elliptic models are obtained by kinematic matching using high-frequency asymptotic, the resulting wavefield contains most of the critical wavefield components, including the frequency dependency and caustics, if present, with reasonable accuracy. The methodology developed here offers a much better cost versus accuracy tradeoff for wavefield computations in TTI media, considering the cost prohibitive nature of the problem. We demonstrate the applicability of the proposed approach on the BP TTI model.
Assessing Model Treatment of Drought Legacy Effects in the Amazon
Kolus, H. R.; Huntzinger, D. N.; Schwalm, C.; Fisher, J. B.; Cook, R. B.; Fang, Y.; Jacobson, A. R.; Michalak, A.; Schaefer, K. M.; Wei, Y.
2015-12-01
Extreme climate events play an important and potentially lasting role in terrestrial carbon cycling and storage. In particular, satellite and in-situ measurements have shown that forest recovery time following severe drought can extend several years beyond the return to normal climate conditions. However, terrestrial ecosystem models generally do not account for the physiological mechanisms that cause these legacy effects and, instead, assume complete and rapid vegetation recovery from drought. Using a suite of fifteen land surface models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we assess models' ability to capture legacy effects by analyzing the spatial and temporal extent of modeled vegetation response to the 2005 Amazon drought. We compare the simulated primary production and ecosystem exchange (GPP, NPP, NEE) to previous recovery-focused analysis of satellite microwave observations of canopy backscatter. Further, we evaluate the specific model characteristics that control the timescale and magnitude of simulated vegetation recovery from drought. Since climate change is expected to increase the frequency and severity of extreme climate events, improving models' ability to simulate the legacy effects of these events will likely refine estimates of the land carbon sink and its interannual variability.
Effect Of Oceanic Lithosphere Age Errors On Model Discrimination
DeLaughter, J. E.
2016-12-01
The thermal structure of the oceanic lithosphere is the subject of a long-standing controversy. Because the thermal structure varies with age, it governs properties such as heat flow, density, and bathymetry with important implications for plate tectonics. Though bathymetry, geoid, and heat flow for young (geoid, and heat flow data to an inverse model to determine lithospheric structure details. Though inverse models usually include the effect of errors in bathymetry, heat flow, and geoid, they rarely examine the effects of errors in age. This may have the effect of introducing subtle biases into inverse models of the oceanic lithosphere. Because the inverse problem for thermal structure is both ill-posed and ill-conditioned, these overlooked errors may have a greater effect than expected. The problem is further complicated by the non-uniform distribution of age and errors in age estimates; for example, only 30% of the oceanic lithosphere is older than 80 MY and less than 3% is older than 150 MY. To determine the potential strength of such biases, I have used the age and error maps of Mueller et al (2008) to forward model the bathymetry for half space and GDH1 plate models. For ages less than 20 MY, both models give similar results. The errors induced by uncertainty in age are relatively large and suggest that when possible young lithosphere should be excluded when examining the lithospheric thermal model. As expected, GDH1 bathymetry converges asymptotically on the theoretical result for error-free data for older data. The resulting uncertainty is nearly as large as that introduced by errors in the other parameters; in the absence of other errors, the models can only be distinguished for ages greater than 80 MY. These results suggest that the problem should be approached with the minimum possible number of variables. For example, examining the direct relationship of geoid to bathymetry or heat flow instead of their relationship to age should reduce uncertainties
Modeling Financial Time Series Based on a Market Microstructure Model with Leverage Effect
Directory of Open Access Journals (Sweden)
Yanhui Xi
2016-01-01
Full Text Available The basic market microstructure model specifies that the price/return innovation and the volatility innovation are independent Gaussian white noise processes. However, the financial leverage effect has been found to be statistically significant in many financial time series. In this paper, a novel market microstructure model with leverage effects is proposed. The model specification assumed a negative correlation in the errors between the price/return innovation and the volatility innovation. With the new representations, a theoretical explanation of leverage effect is provided. Simulated data and daily stock market indices (Shanghai composite index, Shenzhen component index, and Standard and Poor’s 500 Composite index via Bayesian Markov Chain Monte Carlo (MCMC method are used to estimate the leverage market microstructure model. The results verify the effectiveness of the model and its estimation approach proposed in the paper and also indicate that the stock markets have strong leverage effects. Compared with the classical leverage stochastic volatility (SV model in terms of DIC (Deviance Information Criterion, the leverage market microstructure model fits the data better.
Thomas C. Edwards; D. Richard Cutler; Niklaus E. Zimmermann; Linda Geiser; Gretchen G. Moisen
2006-01-01
We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by...
The transition model test for serial dependence in mixed-effects models for binary data
DEFF Research Database (Denmark)
Breinegaard, Nina; Rabe-Hesketh, Sophia; Skrondal, Anders
2016-01-01
Generalized linear mixed models for longitudinal data assume that responses at different occasions are conditionally independent, given the random effects and covariates. Although this assumption is pivotal for consistent estimation, violation due to serial dependence is hard to assess by model...... the targeted root mean squared error of approximation (TRSMEA) as a measure of the population misfit due to serial dependence....
Construction of river model biofilm for assessing pesticide effects.
Hayashi, Shohei; Jang, Ji Eun; Itoh, Kazuhito; Suyama, Kousuke; Yamamoto, Hiroki
2011-01-01
Due to the high importance of biofilms on river ecosystems, assessment of pesticides' adverse effects is necessary but is impaired by high variability and poor reproducibility of both natural biofilms and those developed in the laboratory. We constructed a model biofilm to evaluate the effects of pesticides, consisting in cultured microbial strains, Pedobacter sp. 7-11, Aquaspirillum sp. T-5, Stenotrophomonas sp. 3-7, Achnanthes minutissima N71, Nitzschia palea N489, and/or Cyclotella meneghiniana N803. Microbial cell numbers, esterase activity, chlorophyll-a content, and the community structure of the model biofilm were examined and found to be useful as biological factors for evaluating the pesticide effects. The model biofilm was formed through the cooperative interaction of bacteria and diatoms, and a preliminary experiment using the herbicide atrazine, which inhibits diatom growth, indicated that the adverse effect on diatoms inhibited indirectly the bacterial growth and activity and, thus, the formation of the model biofilm. Toxicological tests using model biofilms could be useful for evaluating the pesticide effects and complementary to studies on actual river biofilms.
Discrete Element Model for Suppression of Coffee-Ring Effect
Xu, Ting; Lam, Miu Ling; Chen, Ting-Hsuan
2017-02-01
When a sessile droplet evaporates, coffee-ring effect drives the suspended particulate matters to the droplet edge, eventually forming a ring-shaped deposition. Because it causes a non-uniform distribution of solid contents, which is undesired in many applications, attempts have been made to eliminate the coffee-ring effect. Recent reports indicated that the coffee-ring effect can be suppressed by a mixture of spherical and non-spherical particles with enhanced particle-particle interaction at air-water interface. However, a model to comprehend the inter-particulate activities has been lacking. Here, we report a discrete element model (particle system) to investigate the phenomenon. The modeled dynamics included particle traveling following the capillary flow with Brownian motion, and its resultant 3D hexagonal close packing of particles along the contact line. For particles being adsorbed by air-water interface, we modeled cluster growth, cluster deformation, and cluster combination. We found that the suppression of coffee-ring effect does not require a circulatory flow driven by an inward Marangoni flow at air-water interface. Instead, the number of new cluster formation, which can be enhanced by increasing the ratio of non-spherical particles and the overall number of microspheres, is more dominant in the suppression process. Together, this model provides a useful platform elucidating insights for suppressing coffee-ring effect for practical applications in the future.
Exotic properties of neutrinos using effective Lagrangians and specific models
Aparici, Alberto
2013-01-01
This doctoral dissertation presents several works on nonstandard properties of neutrinos exploiting the synergies between effective field theory and models. The phenomena are first analysed by means of effective operators, which allow to discuss their phenomenological consequences and to derive estimations about the mass scale of the heavy particles needed to induce the new interactions. In a second phase we propose models that realise the effective operators, allowing us to check the conclusions of effective field theory as well as to extract new phenomenological features of the scenarios considered. The text is divided into two parts: in the first one we apply these ideas to an effective interaction that generates magnetic dipole moments for right-handed neutrinos, and in the second one we discuss a family of operators that violate lepton number without quarks, and which can allow for large rates of neutrinoless double $\\beta$ decay and small neutrino masses. The right-handed neutrino magnetic moments have ...
The problematic estimation of "imitation effects" in multilevel models
Directory of Open Access Journals (Sweden)
2003-09-01
Full Text Available It seems plausible that a person's demographic behaviour may be influenced by that among other people in the community, for example because of an inclination to imitate. When estimating multilevel models from clustered individual data, some investigators might perhaps feel tempted to try to capture this effect by simply including on the right-hand side the average of the dependent variable, constructed by aggregation within the clusters. However, such modelling must be avoided. According to simulation experiments based on real fertility data from India, the estimated effect of this obviously endogenous variable can be very different from the true effect. Also the other community effect estimates can be strongly biased. An "imitation effect" can only be estimated under very special assumptions that in practice will be hard to defend.
Modeling the Effects of Stress: An Approach to Training
Cuper, Taryn
2010-01-01
Stress is an integral element of the operational conditions experienced by combat medics. The effects of stress can compromise the performance of combat medics who must reach and treat their comrades under often threatening circumstances. Examples of these effects include tunnel vision, loss of motor control, and diminished hearing, which can result in an inability to perceive further danger, satisfactorily treat the casualty, and communicate with others. While many training programs strive to recreate this stress to aid in the experiential learning process, stress inducement may not always be feasible or desired. In addition, live simulations are not always a practical, convenient, and repeatable method of training. Instead, presenting situational training on a personal computer is proposed as an effective training platform in which the effects of stress can be addressed in a different way. We explore the cognitive and motor effects of stress, as well as the benefits of training for mitigating these effects in real life. While many training applications focus on inducing stress in order to "condition" the stress response, the author explores the possibilities of modeling stress to produce a similar effect. Can presenting modeled effects of stress help prepare or inoculate soldiers for stressful situations in which they must perform at a high level? This paper investigates feasibility of modeling stress and describes the preliminary design considerations of a combat medic training system that utilizes this method of battlefield preparation.
A sonic boom propagation model including mean flow atmospheric effects
Salamone, Joe; Sparrow, Victor W.
2012-09-01
This paper presents a time domain formulation of nonlinear lossy propagation in onedimension that also includes the effects of non-collinear mean flow in the acoustic medium. The model equation utilized is an augmented Burgers equation that includes the effects of nonlinearity, geometric spreading, atmospheric stratification, and also absorption and dispersion due to thermoviscous and molecular relaxation effects. All elements of the propagation are implemented in the time domain and the effects of non-collinear mean flow are accounted for in each term of the model equation. Previous authors have presented methods limited to showing the effects of wind on ray tracing and/or using an effective speed of sound in their model equation. The present work includes the effects of mean flow for all terms included in the augmented Burgers equation with all of the calculations performed in the time-domain. The capability to include the effects of mean flow in the acoustic medium allows one to make predictions more representative of real-world atmospheric conditions. Examples are presented for nonlinear propagation of N-waves and shaped sonic booms. [Work supported by Gulfstream Aerospace Corporation.
Nonlinear turbulence models for predicting strong curvature effects
Institute of Scientific and Technical Information of China (English)
XU Jing-lei; MA Hui-yang; HUANG Yu-ning
2008-01-01
Prediction of the characteristics of turbulent flows with strong streamline curvature, such as flows in turbomachines, curved channel flows, flows around airfoils and buildings, is of great importance in engineering applicatious and poses a very practical challenge for turbulence modeling. In this paper, we analyze qualitatively the curvature effects on the structure of turbulence and conduct numerical simulations of a turbulent U- duct flow with a number of turbulence models in order to assess their overall performance. The models evaluated in this work are some typical linear eddy viscosity turbulence models, nonlinear eddy viscosity turbulence models (NLEVM) (quadratic and cubic), a quadratic explicit algebraic stress model (EASM) and a Reynolds stress model (RSM) developed based on the second-moment closure. Our numerical results show that a cubic NLEVM that performs considerably well in other benchmark turbulent flows, such as the Craft, Launder and Suga model and the Huang and Ma model, is able to capture the major features of the highly curved turbulent U-duct flow, including the damping of turbulence near the convex wall, the enhancement of turbulence near the concave wall, and the subsequent turbulent flow separation. The predictions of the cubic models are quite close to that of the RSM, in relatively good agreement with the experimental data, which suggests that these inodels may be employed to simulate the turbulent curved flows in engineering applications.
Integrating Multiscale Modeling with Drug Effects for Cancer Treatment.
Li, Xiangfang L; Oduola, Wasiu O; Qian, Lijun; Dougherty, Edward R
2015-01-01
In this paper, we review multiscale modeling for cancer treatment with the incorporation of drug effects from an applied system's pharmacology perspective. Both the classical pharmacology and systems biology are inherently quantitative; however, systems biology focuses more on networks and multi factorial controls over biological processes rather than on drugs and targets in isolation, whereas systems pharmacology has a strong focus on studying drugs with regard to the pharmacokinetic (PK) and pharmacodynamic (PD) relations accompanying drug interactions with multiscale physiology as well as the prediction of dosage-exposure responses and economic potentials of drugs. Thus, it requires multiscale methods to address the need for integrating models from the molecular levels to the cellular, tissue, and organism levels. It is a common belief that tumorigenesis and tumor growth can be best understood and tackled by employing and integrating a multifaceted approach that includes in vivo and in vitro experiments, in silico models, multiscale tumor modeling, continuous/discrete modeling, agent-based modeling, and multiscale modeling with PK/PD drug effect inputs. We provide an example application of multiscale modeling employing stochastic hybrid system for a colon cancer cell line HCT-116 with the application of Lapatinib drug. It is observed that the simulation results are similar to those observed from the setup of the wet-lab experiments at the Translational Genomics Research Institute.
Mathematical modeling of brain tumors: effects of radiotherapy and chemotherapy
Energy Technology Data Exchange (ETDEWEB)
Powathil, G [Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Kohandel, M [Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Sivaloganathan, S [Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Oza, A [Center for Mathematical Medicine, Fields Institute for Research in Mathematical Sciences, Toronto, Ontario M5T 3J1 (Canada); Milosevic, M [Radiation Medicine Program, Princess Margaret Hospital, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)
2007-06-07
Gliomas, the most common primary brain tumors, are diffusive and highly invasive. The standard treatment for brain tumors consists of a combination of surgery, radiation therapy and chemotherapy. Over the past few years, mathematical models have been applied to study untreated and treated brain tumors. In an effort to improve treatment strategies, we consider a simple spatio-temporal mathematical model, based on proliferation and diffusion, that incorporates the effects of radiotherapeutic and chemotherapeutic treatments. We study the effects of different schedules of radiation therapy, including fractionated and hyperfractionated external beam radiotherapy, using a generalized linear quadratic (LQ) model. The results are compared with published clinical data. We also discuss the results for combination therapy (radiotherapy plus temozolomide, a new chemotherapy agent), as proposed in recent clinical trials. We use the model to predict optimal sequencing of the postoperative (combination of radiotherapy and adjuvant, neo-adjuvant or concurrent chemotherapy) treatments for brain tumors.
Effect of automobiles on global warming: A modeling study
Directory of Open Access Journals (Sweden)
Shyam Sundar
2017-09-01
Full Text Available Global warming threatens our environment as well as basic human needs. In the present scenario, increasing demand and excessive use of automobiles have increased the level of carbon dioxide emission in the environment, providing a significant contribution to increase the global warming. This paper deals with the modeling of the effect of automobiles on global warming. For this, three nonlinearly interacting variables namely; density of human population, density of automobiles and the concentration of carbon dioxide have been taken into account. In the modeling process, it is assumed that the density of automobiles increases in proportion to human population following a logistic growth. The model is analyzed using stability theory of ordinary differential equations. Local and global stability conditions are established to study the feasibility of the model system. It is shown that with increase in human population, the demand for automobiles increases which has significant effect on global warming increase.
The Hawking effect in dielectric media and the Hopfield model
Belgiorno, F; Piazza, F Dalla
2014-01-01
We consider the so-called Hopfield model for the electromagnetic field in a dielectric dispersive medium in a framework in which one allows a space-time dependence of microscopic parameters, aimed to a phenomenological description of a space-time varying dielectric perturbation induced by means of the Kerr effect. We discuss the analogue Hawking effect, by first analyzing the geometrical optics for the Hopfield model, and then by introducing a simplified model which has the bonus to avoid many difficulties which are involved in the full Hopfield model, still keeping the same dispersion relation. Amplitude calculations are indicated, and generalized Manley-Rowe identities are derived in a quantum scattering theory framework. Our main result is an analytical calculation of the spontaneous thermal emission in the single-branch case, which is provided non perturbatively for the first time in the framework of dielectric black holes. An universal mechanism for thermality between optical black holes and acoustic bla...
Wang, Hui
2014-05-01
This thesis addresses the efficiency improvement of seismic wave modeling and migration in anisotropic media. This improvement becomes crucial in practice as the process of imaging complex geological structures of the Earth\\'s subsurface requires modeling and migration as building blocks. The challenge comes from two aspects. First, the underlying governing equations for seismic wave propagation in anisotropic media are far more complicated than that in isotropic media which demand higher computational costs to solve. Second, the usage of whole prestack seismic data still remains a burden considering its storage volume and the existing wave equation solvers. In this thesis, I develop two approaches to tackle the challenges. In the first part, I adopt the concept of prestack exploding reflector model to handle the whole prestack data and bridge the data space directly to image space in a single kernel. I formulate the extrapolation operator in a two-way fashion to remove he restriction on directions that waves propagate. I also develop a generic method for phase velocity evaluation within anisotropic media used in this extrapolation kernel. The proposed method provides a tool for generating prestack images without wavefield cross correlations. In the second part of this thesis, I approximate the anisotropic models using effective isotropic models. The wave phenomena in these effective models match that in anisotropic models both kinematically and dynamically. I obtain the effective models through equating eikonal equations and transport equations of anisotropic and isotropic models, thereby in the high frequency asymptotic approximation sense. The wavefields extrapolation costs are thus reduced using isotropic wave equation solvers while the anisotropic effects are maintained through this approach. I benchmark the two proposed methods using synthetic datasets. Tests on anisotropic Marmousi model and anisotropic BP2007 model demonstrate the applicability of my
Modeling size effect in the SMA response: a gradient theory
Tabesh, Majid; Boyd, James G.; Lagoudas, Dimitris C.
2014-03-01
Shape memory alloys (SMAs) show size effect in their response. The critical stresses, for instance, for the start of martensite and austenite transformations are reported to increase in some SMA wires for diameters below 100 μm. Simulation of such a behavior cannot be achieved using conventional theories that lack an intrinsic length scale in their constitutive modeling. To enable the size effect, a thermodynamically consistent constitutive model is developed, that in addition to conventional internal variables of martensitic volume fraction and transformation strain, contains the spatial gradient of martensitic volume fraction as an internal variable. The developed theory is simplified for 1D cases and analytical solutions for pure bending of SMA beams are presented. The gradient model captures the size effect in the response of the studied SMA structures.
Stochastic effects in a seasonally forced epidemic model
Rozhnova, G.; Nunes, A.
2010-10-01
The interplay of seasonality, the system’s nonlinearities and intrinsic stochasticity, is studied for a seasonally forced susceptible-exposed-infective-recovered stochastic model. The model is explored in the parameter region that corresponds to childhood infectious diseases such as measles. The power spectrum of the stochastic fluctuations around the attractors of the deterministic system that describes the model in the thermodynamic limit is computed analytically and validated by stochastic simulations for large system sizes. Size effects are studied through additional simulations. Other effects such as switching between coexisting attractors induced by stochasticity often mentioned in the literature as playing an important role in the dynamics of childhood infectious diseases are also investigated. The main conclusion is that stochastic amplification, rather than these effects, is the key ingredient to understand the observed incidence patterns.
Stochastic effects in a seasonally forced epidemic model
Rozhnova, Ganna
2010-01-01
The interplay of seasonality, the system's nonlinearities and intrinsic stochasticity is studied for a seasonally forced susceptible-exposed-infective-recovered stochastic model. The model is explored in the parameter region that corresponds to childhood infectious diseases such as measles. The power spectrum of the stochastic fluctuations around the attractors of the deterministic system that describes the model in the thermodynamic limit is computed analytically and validated by stochastic simulations for large system sizes. Size effects are studied through additional simulations. Other effects such as switching between coexisting attractors induced by stochasticity often mentioned in the literature as playing an important role in the dynamics of childhood infectious diseases are also investigated. The main conclusion is that stochastic amplification, rather than these effects, is the key ingredient to understand the observed incidence patterns.
Differential Capillary Effect Model of Fabric and Its Application
Institute of Scientific and Technical Information of China (English)
王其; 冯勋伟
2003-01-01
The concept of the differential capillary effect was presented by foreign scholars several years ago, and the principle was used to design sportswear fabrics with good wet permeability and good drying functions for famous sports teams. Because the differential capillary effect model was not established in theory,it was impossible to fulfill the best functions. In this paper, by setting up the differential capillary effect of fabric, the factors to influence wet permeability and drying functions of the model is discussed in theory, and the means to optimize the design of the fabric is presented and proven practically by the experiment. The optimum fabric with good permeability and good drying functions can be designed using the model at last.
Contact Interactions Probe Effective Dark Matter Models at the LHC
Dreiner, Herbi; Tattersall, Jamie
2013-01-01
Effective field theories provide a simple framework for probing possible dark matter (DM) models by reparametrising full interactions into a reduced number of operators with smaller dimensionality in parameter space. In many cases these models have four particle vertices, e.g. qqXX, leading to the pair production of dark matter particles, X, at a hadron collider from initial state quarks, q. In this analysis we show that for many fundamental DM models with s-channel DM couplings to qq-pairs, these effective vertices must also produce quark contact interactions (CI) of the form qqqq. The respective effective couplings are related by the common underlying theory which allows one to translate the upper limits from one coupling to the other. We show that at the LHC, the experimental limits on quark contact interactions give stronger translated limits on the DM coupling than the experimental searches for dark matter pair production.
Memory efficient atmospheric effects modeling for infrared scene generators
Kavak, Çaǧlar; Özsaraç, Seçkin
2015-05-01
The infrared (IR) energy radiated from any source passes through the atmosphere before reaching the sensor. As a result, the total signature captured by the IR sensor is significantly modified by the atmospheric effects. The dominant physical quantities that constitute the mentioned atmospheric effects are the atmospheric transmittance and the atmospheric path radiance. The incoming IR radiation is attenuated by the transmittance and path radiance is added on top of the attenuated radiation. In IR scene simulations OpenGL is widely used for rendering purposes. In the literature there are studies, which model the atmospheric effects in an IR band using OpenGLs exponential fog model as suggested by Beers law. In the standard pipeline of OpenGL, the related fog model needs single equivalent OpenGL variables for the transmittance and path radiance, which actually depend on both the distance between the source and the sensor and also on the wavelength of interest. However, in the conditions where the range dependency cannot be modeled as an exponential function, it is not accurate to replace the atmospheric quantities with a single parameter. The introduction of OpenGL Shading Language (GLSL) has enabled the developers to use the GPU more flexible. In this paper, a novel method is proposed for the atmospheric effects modeling using the least squares estimation with polynomial fitting by programmable OpenGL shader programs built with GLSL. In this context, a radiative transfer model code is used to obtain the transmittance and path radiance data. Then, polynomial fits are computed for the range dependency of these variables. Hence, the atmospheric effects model data that will be uploaded in the GPU memory is significantly reduced. Moreover, the error because of fitting is negligible as long as narrow IR bands are used.
Modeling atmospheric effects of the September 1859 Solar Flare
Thomas, B; Melott, A; Thomas, Brian; Jackman, Charles; Melott, Adrian
2006-01-01
We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1-2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nitrate in our model and compare to values from ice core data.
A Markov model for measuring artillery fire support effectiveness
Guzik, Dennis M.
1988-01-01
Approved for public release; distribution is unlimited This thesis presents a Markov model, which, given an indirect fire weapon system's parameters, yields measures of the weapon's effectiveness in providing fire support to a maneuver element. These parameters may be determined for a variety of different scenarios. Any indirect fire weapon system may be a candidate for evaluation. This model may be used in comparing alternative weapon systems for the role of direct support of a Marin...
Modeling the Substrate Skin Effects in Mutual RL Characteristics.,
Directory of Open Access Journals (Sweden)
D. de Roest
2003-12-01
Full Text Available The goal of this work was to model the influence of the substrateskin effects on the distributed mutual impedance per unit lengthparameters of multiple coupled on-chip interconnects. The proposedanalytic model is based on the frequency-dependent distribution of thecurrent in the silicon substrate and the closed form integrationapproach. It is shown that the calculated frequency-dependentdistributed mutual inductance and the associated mutual resistance arein good agreement with the results obtained from CAD-oriented circuitmodeling technique.
Effective Model Approach to the Dense State of QCD Matter
Fukushima, Kenji
2010-01-01
The first-principle approach to the dense state of QCD matter, i.e. the lattice-QCD simulation at finite baryon density, is not under theoretical control for the moment. The effective model study based on QCD symmetries is a practical alternative. However the model parameters that are fixed by hadronic properties in the vacuum may have unknown dependence on the baryon chemical potential. We propose a new prescription to constrain the effective model parameters by the matching condition with the thermal Statistical Model. In the transitional region where thermal quantities blow up in the Statistical Model, deconfined quarks and gluons should smoothly take over the relevant degrees of freedom from hadrons and resonances. We use the Polyakov-loop coupled Nambu--Jona-Lasinio (PNJL) model as an effective description in the quark side and show how the matching condition is satisfied by a simple ansatz on the Polyakov loop potential. Our results favor a phase diagram with the chiral phase transition located at sligh...
Guidance for modeling causes and effects in environmental problem solving
Armour, Carl L.; Williamson, Samuel C.
1988-01-01
Environmental problems are difficult to solve because their causes and effects are not easily understood. When attempts are made to analyze causes and effects, the principal challenge is organization of information into a framework that is logical, technically defensible, and easy to understand and communicate. When decisionmakers attempt to solve complex problems before an adequate cause and effect analysis is performed there are serious risks. These risks include: greater reliance on subjective reasoning, lessened chance for scoping an effective problem solving approach, impaired recognition of the need for supplemental information to attain understanding, increased chance for making unsound decisions, and lessened chance for gaining approval and financial support for a program/ Cause and effect relationships can be modeled. This type of modeling has been applied to various environmental problems, including cumulative impact assessment (Dames and Moore 1981; Meehan and Weber 1985; Williamson et al. 1987; Raley et al. 1988) and evaluation of effects of quarrying (Sheate 1986). This guidance for field users was written because of the current interest in documenting cause-effect logic as a part of ecological problem solving. Principal literature sources relating to the modeling approach are: Riggs and Inouye (1975a, b), Erickson (1981), and United States Office of Personnel Management (1986).
Predictive modeling of nanomaterial exposure effects in biological systems
Directory of Open Access Journals (Sweden)
Liu X
2013-09-01
Full Text Available Xiong Liu,1 Kaizhi Tang,1 Stacey Harper,2 Bryan Harper,2 Jeffery A Steevens,3 Roger Xu1 1Intelligent Automation, Inc., Rockville, MD, USA; 2Department of Environmental and Molecular Toxicology, School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, USA; 3ERDC Environmental Laboratory, Vicksburg, MS, USA Background: Predictive modeling of the biological effects of nanomaterials is critical for industry and policymakers to assess the potential hazards resulting from the application of engineered nanomaterials. Methods: We generated an experimental dataset on the toxic effects experienced by embryonic zebrafish due to exposure to nanomaterials. Several nanomaterials were studied, such as metal nanoparticles, dendrimer, metal oxide, and polymeric materials. The embryonic zebrafish metric (EZ Metric was used as a screening-level measurement representative of adverse effects. Using the dataset, we developed a data mining approach to model the toxic endpoints and the overall biological impact of nanomaterials. Data mining techniques, such as numerical prediction, can assist analysts in developing risk assessment models for nanomaterials. Results: We found several important attributes that contribute to the 24 hours post-fertilization (hpf mortality, such as dosage concentration, shell composition, and surface charge. These findings concur with previous studies on nanomaterial toxicity using embryonic zebrafish. We conducted case studies on modeling the overall effect/impact of nanomaterials and the specific toxic endpoints such as mortality, delayed development, and morphological malformations. The results show that we can achieve high prediction accuracy for certain biological effects, such as 24 hpf mortality, 120 hpf mortality, and 120 hpf heart malformation. The results also show that the weighting scheme for individual biological effects has a significant influence on modeling the overall impact of
Modelling and Analysis of Proximity Effect in IGBT Fuses
DEFF Research Database (Denmark)
Iov, Florin; Blaabjerg, Frede; Rasmussen, Henrik
2005-01-01
. Even with an active protection, a high power IGBT still has a risk of exhibiting a violent rupture in the case of a fault if e.g. IGBT fuses are not protecting it. By introducing fuses into voltage source converters a better protection of IGBT's can be achieved. However, skin and proximity effects...... affect the current distribution in a fuse due to the high frequency currents and thus a need for de-rating the fuse. This paper shows an analytical model for studying the proximity effect into a fuse. The results obtained using this model are compared with experiments....
Testing cosmological models with the Integrated Sachs-Wolfe effect
Energy Technology Data Exchange (ETDEWEB)
Raccanelli, Alvise, E-mail: alvise.raccanelli@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom)
2011-02-01
The cross correlation between the Cosmic Microwave Background and the Large Scale Structure of the Universe is a powerful probe to test our cosmological models. This correlation can be used to detect the Integrated Sachs-Wolfe effect, and it depends on both the geometry of the Universe and the properties of the clustering and evolution of structures; for this reason it can be used to test and constrain cosmological models and parameters as well as theories of gravity. In this proceeding we briefly introduce the ISW effect and present some of the recent cosmological tests done using it.
A hydrodynamic model for granular material flows including segregation effects
Gilberg, Dominik; Klar, Axel; Steiner, Konrad
2017-06-01
The simulation of granular flows including segregation effects in large industrial processes using particle methods is accurate, but very time-consuming. To overcome the long computation times a macroscopic model is a natural choice. Therefore, we couple a mixture theory based segregation model to a hydrodynamic model of Navier-Stokes-type, describing the flow behavior of the granular material. The granular flow model is a hybrid model derived from kinetic theory and a soil mechanical approach to cover the regime of fast dilute flow, as well as slow dense flow, where the density of the granular material is close to the maximum packing density. Originally, the segregation model has been formulated by Thornton and Gray for idealized avalanches. It is modified and adapted to be in the preferred form for the coupling. In the final coupled model the segregation process depends on the local state of the granular system. On the other hand, the granular system changes as differently mixed regions of the granular material differ i.e. in the packing density. For the modeling process the focus lies on dry granular material flows of two particle types differing only in size but can be easily extended to arbitrary granular mixtures of different particle size and density. To solve the coupled system a finite volume approach is used. To test the model the rotational mixing of small and large particles in a tumbler is simulated.
Development and Validation of a Tokamak Skin Effect Transformer model
Romero, J A; Coda, S; Felici, F; Garrido, I
2012-01-01
A control oriented, lumped parameter model for the tokamak transformer including the slow flux penetration in the plasma (skin effect transformer model) is presented. The model does not require detailed or explicit information about plasma profiles or geometry. Instead, this information is lumped in system variables, parameters and inputs. The model has an exact mathematical structure built from energy and flux conservation theorems, predicting the evolution and non linear interaction of the plasma current and internal inductance as functions of the primary coil currents, plasma resistance, non-inductive current drive and the loop voltage at a specific location inside the plasma (equilibrium loop voltage). Loop voltage profile in the plasma is substituted by a three-point discretization, and ordinary differential equations are used to predict the equilibrium loop voltage as function of the boundary and resistive loop voltages. This provides a model for equilibrium loop voltage evolution, which is reminiscent ...
Effects of Traffic Lights on CA Traffic Model
Institute of Scientific and Technical Information of China (English)
SuweiFENG; GuoqingGU
1997-01-01
Cellular automaton traffic models can include various factors in traffic system with simple regulations and the corresponding computations and simulations are rather convenient and effective.In this paper,the Biham-Middleton-Levine model(briefly saying the BML model)is improved by removing its limitation of synchronized change of traffic lights.In new model,the traffic light at each crossing could arbitrarily change its starting time and tempo of variation and hence the model could more realistically describe the influence of traffic lights on the performance of traffic systems.The cases of traffic light with unsynchronized starting time and different tempo of variation are simulated in this paper.
Validation of a Model of the Domino Effect?
Larham, Ron
2008-01-01
A recent paper proposing a model of the limiting speed of the domino effect is discussed with reference to its need and the need of models in general for validation against experimental data. It is shown that the proposed model diverges significantly from experimentally derived speed estimates over a significant range of domino spacing using data from the existing literature and this author's own measurements, hence if its use had had economic importance its use outside its range of validity could have led to loses of one sort or another to its users.
Excluded volume effect enhances the homology pairing of model chromosomes
Takamiya, Kazunori; Isami, Shuhei; Nishimori, Hiraku; Awazu, Akinori
2015-01-01
To investigate the structural dynamics of the homology pairing of polymers, we mod- eled the scenario of homologous chromosome pairings during meiosis in Schizosaccharomyces pombe, one of the simplest model organisms of eukaryotes. We consider a simple model consist- ing of pairs of homologous polymers with the same structures that are confined in a cylindrical container, which represents the local parts of chromosomes contained in an elongated nucleus of S. pombe. Brownian dynamics simulations of this model showed that the excluded volume effects among non-homological chromosomes and the transitional dynamics of nuclear shape serve to enhance the pairing of homologous chromosomes.
Nuclear EMC effect in non-extensive statistical model
Trevisan, Luis A.; Mirez, Carlos
2013-05-01
In the present work, we attempt to describe the nuclear EMC effect by using the proton structure functions obtained from the non-extensive statistical quark model. We record that such model has three fundamental variables, the temperature T, the radius, and the Tsallis parameter q. By combining different small changes, a good agreement with the experimental data may be obtained. Another interesting point of the model is to allow phenomenological interpretation, for instance, with q constant and changing the radius and the temperature or changing the radius and q and keeping the temperature.
Excluded volume effect enhances the homology pairing of model chromosomes
Takamiya, Kazunori; Yamamoto, Keisuke; Isami, Shuhei; Nishimori, Hiraku; Awazu, Akinori
To investigate the structural dynamics of the homology pairing of polymers, we mod- eled the scenario of homologous chromosome pairings during meiosis in Schizosaccharomyces pombe, one of the simplest model organisms of eukaryotes. We consider a simple model consist- ing of pairs of homologous polymers with the same structures that are confined in a cylindrical container, which represents the local parts of chromosomes contained in an elongated nucleus of S. pombe. Brownian dynamics simulations of this model showed that the excluded volume effects among non-homological chromosomes and the transitional dynamics of nuclear shape serve to enhance the pairing of homologous chromosomes.
Organizational effectiveness. Primary care and the congruence model.
Eiser, A R; Eiser, B J
1996-10-01
The congruence model is a framework used to analyze organizational strengths and weaknesses and pinpoint specific areas for improving effectiveness. This article provides an overview of organizations as open systems, with examples in the primary care arena. It explains and applies the congruence model in the context of primary care issues and functions, including methods by which the model can be used to diagnose organizational problems and generate solutions. Changes needed in primary care due to the managed care environment, and areas of potential problems and sensitivities requiring organizational changes to meet market and regulatory demands now placed on PCOs are examined.
Modelling of the Peltier effect in magnetic multilayers
Juarez-Acosta, Isaac; Olivares-Robles, Miguel A.; Bosu, Subrojati; Sakuraba, Yuya; Kubota, Takahide; Takahashi, Saburo; Takanashi, Koki; Bauer, Gerrit E. W.
2016-02-01
We model the charge, spin, and heat currents in ferromagnetic metal|normal metal|normal metal trilayer structures in the two current model, taking into account bulk and interface thermoelectric properties as well as Joule heating. The results include the temperature distribution as well as resistance-current curves that reproduce the observed shifted parabolic characteristics. Thin tunneling barriers can enhance the apparent Peltier cooling. The model agrees with the experimental results for wide multilayer pillars, but the giant effects observed for diameters ≲100 nm are still under discussion.
Numerical modeling of coanda effect in a novel propulsive system
Directory of Open Access Journals (Sweden)
S Das
2016-09-01
Full Text Available Coanda effect (adhesion of jet flow over curved surface is fundamental characteristics of jet flow. In the present paper, we carried out numerical simulations to investigate Coanda flow over a curved surface and its application in a newly proposed Propulsive system "A.C.H.E.O.N" (Aerial Coanda High Efficiency Orienting jet Nozzle which supports thrust vectoring. The ACHEON system is presently being proposed for propelling a new V/STOL airplane in European Union. This system is based on cumulative effects of three physical effects such as (1 High speed jet mixing speeds (2 Coanda effect control by electrostatic fields (3 Coanda effect adhesion of an high speed jet to a convex surface. The performance of this nozzle can be enhanced by increasing the jet deflection angle of synthetic jet over the Coanda surface. This newly proposed nozzle has wide range of applications. It can be used in industrial sector such as plasma spray gun and for direct injection in combustion chamber to enhance the efficiency of the combustion chamber. Also, we studied the effect of Dielectric barrier discharge (DBD plasma actuators on A.C.H.E.O.N system. Dielectric barrier discharge (DBD plasma actuators are active control devices for controlling boundary layer and to delay the flow separation over any convex surfaces. Computations were performed under subsonic condition. Two dimensional CFD calculations were carried out using Reynolds averaged Navier stokes equations (RANS. A numerical method based on finite volume formulation (FVM was used. SST k-ω model was considered to model turbulent flow inside nozzle. DBD model was used to model the plasma. Moreover, a body force treatment was devised to model the effect of plasma and its coupling with the fluid. This preliminary result shows that, the presence of plasma near Coanda surface accelerates the flow and delays the separation and enhances the efficiency of the nozzle.
A Composite Model of Quarks with the `Effective Supersymmetry'
Okada, N.
1998-04-01
We present a composite model of quarks with `effective supersymmetry'. The model is based on the gauge group (SU(2)S × SU(2)M) × (SU(2)U × SU(2)C × SU(2)T) × SU(5)SM , where SU(5)SM is the standard model gauge group. In the dynamical supersymmetry breaking sector based on the gauge group SU(2)S × SU(2)M , supersymmetry is dynamically broken. The preon sector is constructed by the model proposed by Nelson and Strassler. The fermion mass hierarchy among the up-type quarks originates from the SU(2)U × SU(2)C × SU(2)T gauge dynamics. The supersymmetry breaking is mediated to the minimal supersymmetric standard model sector by the `preon' superfields which compose the quarks in the first two generations. To obtain an experimentally acceptable mass spectrum, the scalar quarks in the first two generations need masses of order 10 TeV, while the other superpartners need masses less than 1 TeV. Therefore, the mass spectrum in our model is one example of the `effective supersymmetry' model proposed by Cohen, Kaplan and Nelson.
A Composite Model of Quarks with the "Effective Supersymmetry"
Okada, N
1998-01-01
We present a composite model of quarks with the `effective supersymmetry'. The model is based on the gauge group $(SU(2)_S \\times SU(2)_M) \\times (SU(2)_U standard model gauge group. In the dynamical supersymmetry breaking sector based on the gauge group $ SU(2)_S \\times SU(2)_M $, the supersymmetry is dynamically broken. The preon sector is constructed by the model proposed by Nelson and Strassler. The fermion mass hierarchy among the up-type quarks originates from the $ SU(2)_U \\times SU(2)_C \\times SU(2)_T $ gauge dynamics. The supersymmetry breaking is mediated to the minimal supersymmetric standard model sector by the `preon' superfields which compose the quarks in the first two generations. To obtain the experimentally acceptable mass spectrum, the scalar quarks in the first two generations have masses of order 10 TeV, while the other superpartners have masses of order 100 GeV. Therefore, the mass spectrum in our model is one of the type of the `effective supersymmetry' model proposed by Cohen, Kaplan a...
Modelling QTL effect on BTA06 using random regression test day models.
Suchocki, T; Szyda, J; Zhang, Q
2013-02-01
In statistical models, a quantitative trait locus (QTL) effect has been incorporated either as a fixed or as a random term, but, up to now, it has been mainly considered as a time-independent variable. However, for traits recorded repeatedly, it is very interesting to investigate the variation of QTL over time. The major goal of this study was to estimate the position and effect of QTL for milk, fat, protein yields and for somatic cell score based on test day records, while testing whether the effects are constant or variable throughout lactation. The analysed data consisted of 23 paternal half-sib families (716 daughters of 23 sires) of Chinese Holstein-Friesian cattle genotyped at 14 microsatellites located in the area of the casein loci on BTA6. A sequence of three models was used: (i) a lactation model, (ii) a random regression model with a QTL constant in time and (iii) a random regression model with a QTL variable in time. The results showed that, for each production trait, at least one significant QTL exists. For milk and protein yields, the QTL effect was variable in time, while for fat yield, each of the three models resulted in a significant QTL effect. When a QTL is incorporated into a model as a constant over time, its effect is averaged over lactation stages and may, thereby, be difficult or even impossible to be detected. Our results showed that, in such a situation, only a longitudinal model is able to identify loci significantly influencing trait variation.
Revisiting the Carrington Event: Updated modeling of atmospheric effects
Thomas, Brian C; Snyder, Brock R
2011-01-01
The terrestrial effects of major solar events such as the Carrington white-light flare and subsequent geomagnetic storm of August-September 1859 are of considerable interest, especially in light of recent predictions that such extreme events will be more likely over the coming decades. Here we present results of modeling the atmospheric effects, especially production of odd nitrogen compounds and subsequent depletion of ozone, by solar protons associated with the Carrington event. This study combines approaches from two previous studies of the atmospheric effect of this event. We investigate changes in NOy compounds as well as depletion of O3 using a two-dimensional atmospheric chemistry and dynamics model. Atmospheric ionization is computed using a range-energy relation with four different proxy proton spectra associated with more recent well-known solar proton events. We find that changes in atmospheric constituents are in reasonable agreement with previous studies, but effects of the four proxy spectra use...
Energy Technology Data Exchange (ETDEWEB)
Bergami, L.; Gaunaa, M.
2012-02-15
The report presents the ATEFlap aerodynamic model, which computes the unsteady lift, drag and moment on a 2D airfoil section equipped with Adaptive Trailing Edge Flap. The model captures the unsteady response related to the effects of the vorticity shed into the wake, and the dynamics of flow separation a thin-airfoil potential flow model is merged with a dynamic stall model of the Beddoes-Leishmann type. The inputs required by the model are steady data for lift, drag, and moment coefficients as function of angle of attack and flap deflection. Further steady data used by the Beddoes- Leishmann dynamic stall model are computed in an external preprocessor application, which gives the user the possibility to verify, and eventually correct, the steady data passed to the aerodynamic model. The ATEFlap aerodynamic model is integrated in the aeroelastic simulation tool HAWC2, thus al- lowing to simulate the response of a wind turbine with trailing edge flaps on the rotor. The algorithms used by the preprocessor, and by aerodynamic model are presented, and modifications to previous implementations of the aerodynamic model are briefly discussed. The performance and the validity of the model are verified by comparing the dynamic response computed by the ATEFlap with solutions from CFD simulations. (Author)
THE EFFECTS OF THE ACTIVE LEARNING MODEL ON STUDENTS
Directory of Open Access Journals (Sweden)
Müge TAÇMAN
2007-06-01
Full Text Available The main purpose of this research was to determine the effects of the active learning model onstudents. The subjects were 40 teacher candidates from computer and teaching technology department who were enrolled inthe course of “New Instructional Methods” at Near East University in TRNC. A queationnaires were used to collect the data.The data was analyzed by using frequencies and percentile techniques. The finding revealed that there was a positive effect ofavtive learning atmosphere on students.
Pseudospectral Model for Hybrid PIC Hall-effect Thruster Simulation
2015-07-01
1149. 8Goebel, D. M. and Katz, I., Fundamentals of Electric Propulsion : Ion and Hall Thrusters, John Wiley & Sons, Inc., 2008. 9Martin, R., J.W., K...Bilyeu, D., and Tran, J., “Dynamic Particle Weight Remapping in Hybrid PIC Hall -effect Thruster Simulation,” 34th Int. Electric Propulsion Conf...Paper 3. DATES COVERED (From - To) July 2015-July 2015 4. TITLE AND SUBTITLE Pseudospectral model for hybrid PIC Hall -effect thruster simulationect
Three-dimensional effects for radio frequency antenna modeling
Energy Technology Data Exchange (ETDEWEB)
Carter, M.D.; Batchelor, D.B.; Stallings, D.C.
1993-09-01
Electromagnetic field calculations for radio frequency (rf) antennas in two dimensions (2-D) neglect finite antenna length effects as well as the feeders leading to the main current strap. Comparisons with experiments indicate that these 2-D calculations can overestimate the loading of the antenna and fail to give the correct reactive behavior. To study the validity of the 2-D approximation, the Multiple Antenna Implementation System (MAntIS) has been used to perform 3-D modeling of the power spectrum, plasma loading, and inductance for a relevant loop antenna design. Effects on antenna performance caused by feeders to the main current strap, conducting sidewalls, and finite phase velocity are considered. The plasma impedance matrix for the loading calculation is generated by use of the ORION-1D code. The 3-D model is benchmarked with the 2-D model in the 2-D limit. For finite-length antennas, inductance calculations are found to be in much more reasonable agreement with experiments for 3-D modeling than for the 2-D estimates. The modeling shows that the feeders affect the launched power spectrum in an indirect way by forcing the driven rf current to return in the antenna sidewalls rather than in the plasma as in the 2-D model. Thus, the feeders have much more influence than the plasma on the currents that return in the sidewall. It has also been found that poloidal dependencies in the plasma impedance matrix can reduce the loading from that predicted in the 2-D model. For some plasma parameters, the combined 3-D effects can lead to a reduction in the predicted loading by as much as a factor of 2 from that given by the 2-D model.
Modeling the effect of comprehensive interventions on Ebola virus transmission
Shen, Mingwang; Xiao, Yanni; Rong, Libin
2015-10-01
Since the re-emergence of Ebola in West Africa in 2014, comprehensive and stringent interventions have been implemented to decelerate the spread of the disease. The effectiveness of interventions still remains unclear. In this paper, we develop an epidemiological model that includes various controlling measures to systematically evaluate their effects on the disease transmission dynamics. By fitting the model to reported cumulative cases and deaths in Guinea, Sierra Leone and Liberia until March 22, 2015, we estimate the basic reproduction number in these countries as 1.2552, 1.6093 and 1.7994, respectively. Model analysis shows that there exists a threshold of the effectiveness of isolation, below which increasing the fraction of latent individuals diagnosed prior to symptoms onset or shortening the duration between symptoms onset and isolation may lead to more Ebola infection. This challenges an existing view. Media coverage plays a substantial role in reducing the final epidemic size. The response to reported cumulative infected cases and deaths may have a different effect on the epidemic spread in different countries. Among all the interventions, we find that shortening the duration between death and burial and improving the effectiveness of isolation are two effective interventions for controlling the outbreak of Ebola virus infection.
High-resolution DEM Effects on Geophysical Flow Models
Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.
2014-12-01
Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (<10-15°) slope angles are involved. At these slope angles, multiple adjacent DEM cell elevation values are equal due to the need for the DEM to approximate the low slope with a limited set of integer values for elevation. The first derivative of the elevation surface thus becomes zero. In these cases, flow propagation is inhibited by these spurious zero-slope conditions. Here we present evidence for this "terracing effect" from 1) a mathematically defined simulated elevation model, to demonstrate the terracing effects of integer valued data, and 2) a real-world DEM where terracing must be
Contagion effects in a chartist fundamentalist model with time delays
Dibeh, Ghassan
2007-08-01
In this paper two models of speculative markets are developed to study the effects of feedback mechanisms in financial markets. In the first model, a crash market model couples a linear chartist-fundamentalist model with time delays with a log-periodic market index I(t) through direct coupling. Numerical solutions to the model show that asset prices exhibit significant persistence as a result of the coupling to the log-periodic market index. An extension to include endogenous wealth dynamics shows that the chartists benefit from the persistent dynamics induced by the coupling. The second model is a two-asset model represented by a 2-dimensional delay-differential equation. Asset one price exhibits limit cycle dynamics while in the second market asset prices follow stable damped oscillations. The markets are coupled through a diffusive coupling term. Solutions to the coupled model show that the dynamics of asset two changes fundamentally with the price now exhibiting a limit cycle. The stable converging dynamics is replaced with limit cycle oscillations around the fundamental.
Sequential Effects in Essay Ratings: Evidence of Assimilation Effects Using Cross-Classified Models.
Zhao, Haiyan; Andersson, Björn; Guo, Boliang; Xin, Tao
2017-01-01
Writing assessments are an indispensable part of most language competency tests. In our research, we used cross-classified models to study rater effects in the real essay rating process of a large-scale, high-stakes educational examination administered in China in 2011. Generally, four cross-classified models are suggested for investigation of rater effects: (1) the existence of sequential effects, (2) the direction of the sequential effects, and (3) differences in raters by their individual characteristics. We applied these models to the data to account for possible cluster effects caused by the application of multiple rating strategies. The results of our research showed that raters demonstrated sequential effects during the rating process. In contrast to many other studies on rater effects, our study found that raters exhibited assimilation effects. The more experienced, lenient, and qualified raters were less susceptible to assimilation effects. In addition, our research demonstrated the feasibility and appropriateness of using cross-classified models in assessing rater effects for such data structures. This paper also discusses the implications for educators and practitioners who are interested in reducing sequential effects in the rating process, and suggests directions for future research.
Fennel, Katja; Laurent, Arnaud; Hetland, Robert; Justić, Dubravko; Ko, Dong S.; Lehrter, John; Murrell, Michael; Wang, Lixia; Yu, Liuqian; Zhang, Wenxia
2016-08-01
A large hypoxic zone forms every summer on the Texas-Louisiana Shelf in the northern Gulf of Mexico due to nutrient and freshwater inputs from the Mississippi/Atchafalaya River System. Efforts are underway to reduce the extent of hypoxic conditions through reductions in river nutrient inputs, but the response of hypoxia to such nutrient load reductions is difficult to predict because biological responses are confounded by variability in physical processes. The objective of this study is to identify the major physical model aspects that matter for hypoxia simulation and prediction. In order to do so, we compare three different circulation models (ROMS, FVCOM, and NCOM) implemented for the northern Gulf of Mexico, all coupled to the same simple oxygen model, with observations and against each other. By using a highly simplified oxygen model, we eliminate the potentially confounding effects of a full biogeochemical model and can isolate the effects of physical features. In a systematic assessment, we found that (1) model-to-model differences in bottom water temperatures result in differences in simulated hypoxia because temperature influences the uptake rate of oxygen by the sediments (an important oxygen sink in this system), (2) vertical stratification does not explain model-to-model differences in hypoxic conditions in a straightforward way, and (3) the thickness of the bottom boundary layer, which sets the thickness of the hypoxic layer in all three models, is key to determining the likelihood of a model to generate hypoxic conditions. These results imply that hypoxic area, the commonly used metric in the northern Gulf which ignores hypoxic layer thickness, is insufficient for assessing a model's ability to accurately simulate hypoxia, and that hypoxic volume needs to be considered as well.
Effect of Keishibukuryogan on Genetic and Dietary Obesity Models
Directory of Open Access Journals (Sweden)
Fengying Gao
2015-01-01
Full Text Available Obesity has been recognized as one of the most important risk factors for a variety of chronic diseases, such as diabetes, hypertension/cardiovascular diseases, steatosis/hepatitis, and cancer. Keishibukuryogan (KBG, Gui Zhi Fu Ling Wan in Chinese is a traditional Chinese/Japanese (Kampo medicine that has been known to improve blood circulation and is also known for its anti-inflammatory or scavenging effect. In this study, we evaluated the effect of KBG in two distinct rodent models of obesity driven by either a genetic (SHR/NDmcr-cp rat model or dietary (high-fat diet-induced mouse obesity model mechanism. Although there was no significant effect on the body composition in either the SHR rat or the DIO mouse models, KBG treatment significantly decreased the serum level of leptin and liver TG level in the DIO mouse, but not in the SHR rat model. Furthermore, a lower fat deposition in liver and a smaller size of adipocytes in white adipose tissue were observed in the DIO mice treated with KBG. Importantly, we further found downregulation of genes involved in lipid metabolism in the KBG-treated liver, along with decreased liver TG and cholesterol level. Our present data experimentally support in fact that KBG can be an attractive Kampo medicine to improve obese status through a regulation of systemic leptin level and/or lipid metabolism.
Bello, Nora M; Steibel, Juan P; Tempelman, Robert J
2010-06-01
Bivariate mixed effects models are often used to jointly infer upon covariance matrices for both random effects (u) and residuals (e) between two different phenotypes in order to investigate the architecture of their relationship. However, these (co)variances themselves may additionally depend upon covariates as well as additional sets of exchangeable random effects that facilitate borrowing of strength across a large number of clusters. We propose a hierarchical Bayesian extension of the classical bivariate mixed effects model by embedding additional levels of mixed effects modeling of reparameterizations of u-level and e-level (co)variances between two traits. These parameters are based upon a recently popularized square-root-free Cholesky decomposition and are readily interpretable, each conveniently facilitating a generalized linear model characterization. Using Markov Chain Monte Carlo methods, we validate our model based on a simulation study and apply it to a joint analysis of milk yield and calving interval phenotypes in Michigan dairy cows. This analysis indicates that the e-level relationship between the two traits is highly heterogeneous across herds and depends upon systematic herd management factors.
O'Malley, A James; Christakis, Nicholas A
2011-04-30
We develop novel mixed effects models to examine the role of health traits on the status of peoples' close friendship nominations in the Framingham Heart Study. The health traits considered are both mutable (body mass index (BMI), smoking, blood pressure, body proportion, muscularity, and depression) and, for comparison, basically immutable (height, birth order, personality type, only child, and handedness); and the traits have varying degrees of observability. We test the hypotheses that existing ties (i.e. close friendship nominations) are more likely to dissolve between people with dissimilar (mutable and observable) health traits whereas new ties are more likely to form between those with similar (mutable and observable) traits while controlling for persons' age, gender, geographic separation, and education. The mixed effects models contain random effects for both the nominator (ego) and nominated (alter) persons in a tie to account for the fact that people were involved in multiple relationships and contributed observations at multiple exams. Results for BMI support the hypotheses that people of similar BMI are less likely to dissolve existing ties and more likely to form ties, while smoker to non-smoker ties were the least likely to dissolve and smoker to smoker ties were the most likely to form. We also validated previously known findings regarding homophily on age and gender, and found evidence that homophily also depends upon geographic separation. Copyright © 2011 John Wiley & Sons, Ltd.
Synaptic channel model including effects of spike width variation
2015-01-01
Synaptic Channel Model Including Effects of Spike Width Variation Hamideh Ramezani Next-generation and Wireless Communications Laboratory (NWCL) Department of Electrical and Electronics Engineering Koc University, Istanbul, Turkey Ozgur B. Akan Next-generation and Wireless Communications Laboratory (NWCL) Department of Electrical and Electronics Engineering Koc University, Istanbul, Turkey ABSTRACT An accu...
Varying parameter models to accommodate dynamic promotion effects
Foekens, E.W.; Leeflang, P.S.H.; Wittink, D.R.
1999-01-01
The purpose of this paper is to examine the dynamic effects of sales promotions. We create dynamic brand sales models (for weekly store-level scanner data) by relating store intercepts and a brand's own price elasticity to a measure of the cumulated previous price discounts - amount and time - for t
Effects of Cueing and Modeling Variables in Teacher Training Systems.
Orme, Michael E. J.
Theoretical considerations suggest that the differential effectiveness of teaching models and associated feedback procedures stems from their distinctive cueing properties. This led to the development of three treatment conditions which may be labeled "rating" (rehearsal of key discriminations), "observation" vicarious reinforcement), and "direct…
Modeling of eating style and its effect on intake
Boer, van den J.H.W.; Mars, M.
2015-01-01
Observational research has indicated that modeling of eating style might occur when eating in the presence of an eating companion. This experiment investigated the effect of bite frequency of a same-sex eating companion on bite frequency, meal size and meal duration. A total of 30 normal weight youn
Deriving dynamic marketing effectiveness from econometric time series models
C. Horváth (Csilla); Ph.H.B.F. Franses (Philip Hans)
2003-01-01
textabstractTo understand the relevance of marketing efforts, it has become standard practice to estimate the long-run and short-run effects of the marketing-mix, using, say, weekly scanner data. A common vehicle for this purpose is an econometric time series model. Issues that are addressed in the
Contrasting effects of sunitinib within in vivo models of metastasis
DEFF Research Database (Denmark)
Welti, Jonathan C; Powles, Thomas; Foo, Shane
2012-01-01
Sunitinib is a potent and clinically approved tyrosine kinase inhibitor that can suppress tumour growth by inhibiting angiogenesis. However, conflicting data exist regarding the effects of this drug on the growth of metastases in preclinical models. Here we use 4T1 and RENCA tumour cells, which b...
QUANTUM SIZE EFFECTS IN THE ATTRACTIVE HUBBARD-MODEL
BORMANN, D; SCHNEIDER, T; FRICK, M
1992-01-01
We investigate superconducting pair correlations in the attractive Hubbard model on a finite square lattice. Our aim is to understand the pronounced size dependence which they display in the weak and intermediate coupling regimes. These size effects originate from the electronic shell structure of f
Towards a more effective model for distance education
Koper, Rob
2014-01-01
Reference: Koper, E.J.R. (2014). Towards a more effective model for distance education. e-Learning and Education. e-Learning and Education, 10. urn:nbn:de:0009-5-40105 http://eleed.campussource.de/archive/10/4010
Maximizing the Effectiveness of Leadership Inservice Education: An Operational Model.
Sommerville, Joseph C.
This paper includes a functional model for upgrading the effectiveness of inservice training for school administrators. It is based on the writer's contention that most inservice programs for administrators do not relate to the leadership concerns of each participant, skills developed in those programs often are not applied to the participant's…
An Integrated Model for Effective Knowledge Management in Chinese Organizations
An, Xiaomi; Deng, Hepu; Wang, Yiwen; Chao, Lemen
2013-01-01
Purpose: The purpose of this paper is to provide organizations in the Chinese cultural context with a conceptual model for an integrated adoption of existing knowledge management (KM) methods and to improve the effectiveness of their KM activities. Design/methodology/approaches: A comparative analysis is conducted between China and the western…
Effective ellipsoidal models for wavefield extrapolation in tilted orthorhombic media
Waheed, Umair Bin
2016-04-22
Wavefield computations using the ellipsoidally anisotropic extrapolation operator offer significant cost reduction compared to that for the orthorhombic case, especially when the symmetry planes are tilted and/or rotated. However, ellipsoidal anisotropy does not provide accurate wavefield representation or imaging for media of orthorhombic symmetry. Therefore, we propose the use of ‘effective ellipsoidally anisotropic’ models that correctly capture the kinematic behaviour of wavefields for tilted orthorhombic (TOR) media. We compute effective velocities for the ellipsoidally anisotropic medium using kinematic high-frequency representation of the TOR wavefield, obtained by solving the TOR eikonal equation. The effective model allows us to use the cheaper ellipsoidally anisotropic wave extrapolation operators. Although the effective models are obtained by kinematic matching using high-frequency asymptotic, the resulting wavefield contains most of the critical wavefield components, including frequency dependency and caustics, if present, with reasonable accuracy. The proposed methodology offers a much better cost versus accuracy trade-off for wavefield computations in TOR media, particularly for media of low to moderate anisotropic strength. Furthermore, the computed wavefield solution is free from shear-wave artefacts as opposed to the conventional finite-difference based TOR wave extrapolation scheme. We demonstrate applicability and usefulness of our formulation through numerical tests on synthetic TOR models. © 2016 Institute of Geophysics of the ASCR, v.v.i
Effective action for EPRL/FK spin foam models
Mikovic, Aleksandar
2011-01-01
We show that a natural modification of the EPRL/FK vertex amplitude gives a finite spin foam model whose effective action gives the Einstein-Hilbert action in the limit of large spins and arbitrarily fine spacetime triangulations. The first-order quantum corrections can be easily computed and we show how to calculate the higher-order corrections.
Effects of modeling versus instructions on sensitivity to reinforcement schedules.
Neef, Nancy A.; Marckel, Julie; Ferreri, Summer; Jung, Sunhwa; Nist, Lindsay; Armstrong, Nancy
2004-01-01
This study examined the effects of modeling versus instructions on the choices of 3 typically developing children and 3 children with attention deficit hyperactivity disorder (ADHD) whose academic responding showed insensitivity to reinforcement schedules. During baseline, students chose between successively presented pairs of mathematics problems associated with different variable-interval schedules of reinforcement. After responding proved insensitive to the schedules, sessions were precede...
Modeling the Constructs Contributing to the Effectiveness of Marketing Lecturers
Sweeney, Arthur D. P.; Morrison, Mark D.; Jarratt, Denise; Heffernan, Troy
2009-01-01
Student evaluation of teaching has been examined in higher education research for over 70 years but there are gaps in our knowledge about the contribution, and relationships between, the relevant constructs. Recent literature encourages researchers to test multivariate models of Teaching Effectiveness. Seven main constructs known to influence…
STAS and Logit Modeling of Advertising and Promotion Effects
DEFF Research Database (Denmark)
Hansen, Flemming; Yssing Hansen, Lotte; Grønholdt, Lars
2002-01-01
This paper describes the preliminary studies of the effect of advertising and promotion on purchases using the British single-source database Adlab. STAS and logit modeling are the two measures studied. Results from the two measures have been compared to determine the extent to which, they give...
The Coriolis Effect: A Model for Student Involvement
Exline, Joseph D.
1977-01-01
Lists materials and procedures for constructing a model that demonstrates certain aspects of the Coriolis effect. Materials include an electric drill motor, voltage control, toy dart gun and darts, wood blocks of varying dimensions. Includes description of an experiment illustrating relationship between speed of rotation and amount of apparent…
Varying parameter models to accommodate dynamic promotion effects
Foekens, E.W.; Leeflang, P.S.H.; Wittink, D.R.
1999-01-01
The purpose of this paper is to examine the dynamic effects of sales promotions. We create dynamic brand sales models (for weekly store-level scanner data) by relating store intercepts and a brand's own price elasticity to a measure of the cumulated previous price discounts - amount and time - for
Performance of Random Effects Model Estimators under Complex Sampling Designs
Jia, Yue; Stokes, Lynne; Harris, Ian; Wang, Yan
2011-01-01
In this article, we consider estimation of parameters of random effects models from samples collected via complex multistage designs. Incorporation of sampling weights is one way to reduce estimation bias due to unequal probabilities of selection. Several weighting methods have been proposed in the literature for estimating the parameters of…
CREATING EFFECTIVE MODELS OF VERTICAL INTEGRATED STRUCTURES IN UKRAINE
Directory of Open Access Journals (Sweden)
D. V. Koliesnikov
2011-01-01
Full Text Available The results of scientific research aimed at development of methodology-theoretical mechanisms of building the effective models of vertically-integrated structures are presented. A presence of vertically-integrated structures on natural-monopolistic markets at private and governmental sectors of economy and priority directions of integration are given.
Modeling of eating style and its effect on intake
Boer, van den J.H.W.; Mars, M.
2015-01-01
Observational research has indicated that modeling of eating style might occur when eating in the presence of an eating companion. This experiment investigated the effect of bite frequency of a same-sex eating companion on bite frequency, meal size and meal duration. A total of 30 normal weight youn
A Conceptual Model for Effective Distance Learning in Higher Education
Farajollahi, Mehran; Zare, Hosein; Hormozi, Mahmood; Sarmadi, Mohammad Reza; Zarifsanaee, Nahid
2010-01-01
The present research aims at presenting a conceptual model for effective distance learning in higher education. Findings of this research shows that an understanding of the technological capabilities and learning theories especially constructive theory and independent learning theory and communicative and interaction theory in Distance learning is…
Longitudinal mixed-effects models for latent cognitive function
Hout, van den Ardo; Fox, Jean-Paul; Muniz-Terrera, Graciela
2015-01-01
A mixed-effects regression model with a bent-cable change-point predictor is formulated to describe potential decline of cognitive function over time in the older population. For the individual trajectories, cognitive function is considered to be a latent variable measured through an item response t
Key Elements of Effective Teaching in the Direct Teaching Model.
Bruning, Roger H.
Summaries and outlines are presented of key elements in effective teaching identified in research studies by Kounin (1970), Brophy (1973), Brophy and Evertson (1976), Stallings (1974; l975), Berliner (1979), and Good and Grouws (1979). These elements are synthesized in a direct teaching model that delineates the characteristics of effective…
Effective single scattering albedo estimation using regional climate model
CSIR Research Space (South Africa)
Tesfaye, M
2011-09-01
Full Text Available In this study, by modifying the optical parameterization of Regional Climate model (RegCM), the authors have computed and compared the Effective Single-Scattering Albedo (ESSA) which is a representative of VIS spectral region. The arid, semi...
Modeling of eating style and its effect on intake
Boer, van den J.H.W.; Mars, M.
2015-01-01
Observational research has indicated that modeling of eating style might occur when eating in the presence of an eating companion. This experiment investigated the effect of bite frequency of a same-sex eating companion on bite frequency, meal size and meal duration. A total of 30 normal weight
Compact model for switching characteristics of graphene field effect transistor
Sreenath, R.; Bala Tripura Sundari, B.
2016-04-01
The scaling of CMOS transistors has resulted in intensified short channel effects, indicating that CMOS has reached its physical limits. Alternate non silicon based materials namely carbon based graphene, carbon nanotubes are being explored for usability as channel and interconnect material due to their established higher mobility and robustness. This paper presents a drift-diffusion based circuit simulatable Verilog-A compact model of graphene field effect transistor (GFET) for channel length of 100nm.The focus is on the development of simulatable device model in Verilog A based on intrinsic parameters and obtain the current, high cutoff frequency and use the model into circuit level simulations to realize an inverter and a 3-stage ring oscillator using Synopsys HSPICE. The applications are so chosen that their switching characteristics enable the determination of the RF frequency ranges of operation that the model can achieve when used in digital applications and also to compare its performance with existing CMOS model. The GFET's switching characteristics and power consumption were found to be better than similarly sized CMOS operating at same range of voltages. The basic frequency of operation in the circuit is of significant importance so as to use the model in other applications at RF and in future for millimeter wave applications. The frequency of operation at circuit level is found to be 1.1GHz at 100nm which is far higher than the existing frequency of 245 MHz reported at 500nm using AlN.
Effects of subgrid-scale modeling on wind turbines flows
Ciri, Umberto; Salvetti, Maria Vittoria; Leonardi, Stefano
2015-11-01
The increased demand for wind energy had led to a continuous increase in the size of wind turbines and, consequently, of wind farms. A potential drawback of such large clusters lies in the decrease in the efficiency due to the wake interference. Large-Eddy Simulations (LES) coupled with blade models have shown the capability of resolving the unsteady nature of wind turbine wakes. In LES, subgrid-scale (SGS) models are needed to introduce the effect of the turbulence small scales not resolved by the computational grid. Many LES of wind farms employ the classic Smagorinsky model, despite it suffers from some major drawbacks, e.g. (i) the presence of an input tuning parameter and (ii) the wrong behaviour near solid walls. In the present work an analysis of the effects of various SGS models is carried out for LES in which the turbine tower and nacelle are directly simulated with the Immersed Boundaries method. Particular attention is dedicated to the region of separated flow behind the tower where the impact of the SGS models is expected to be important. We focus herein on non-dynamic eddy-viscosity models, which have proven to have a correct behaviour near solid walls. A priori and a posteriori tests are performed for a configuration reproducing an experiment conducted at NTNU. The work is partially supported by the NSF PIRE Award IIA 1243482. TACC is acknowledged for providing computational time.
Transmission Model of Hepatitis B Virus with the Migration Effect
Directory of Open Access Journals (Sweden)
Muhammad Altaf Khan
2013-01-01
Full Text Available Hepatitis B is a globally infectious disease. Mathematical modeling of HBV transmission is an interesting research area. In this paper, we present characteristics of HBV virus transmission in the form of a mathematical model. We analyzed the effect of immigrants in the model to study the effect of immigrants for the host population. We added the following flow parameters: “the transmission between migrated and exposed class” and “the transmission between migrated and acute class.” With these new features, we obtained a compartment model of six differential equations. First, we find the basic threshold quantity Ro and then find the local asymptotic stability of disease-free equilibrium and endemic equilibrium. Furthermore, we find the global stability of the disease-free and endemic equilibria. Previous similar publications have not added the kind of information about the numerical results of the model. In our case, from numerical simulation, a detailed discussion of the parameters and their numerical results is presented. We claim that with these assumptions and by adding the migrated class, the model informs policy for governments, to be aware of the immigrants and subject them to tests about the disease status. Immigrants for short visits and students should be subjected to tests to reduce the number of immigrants with disease.
Transmission model of hepatitis B virus with the migration effect.
Khan, Muhammad Altaf; Islam, Saeed; Arif, Muhammad; ul Haq, Zahoor
2013-01-01
Hepatitis B is a globally infectious disease. Mathematical modeling of HBV transmission is an interesting research area. In this paper, we present characteristics of HBV virus transmission in the form of a mathematical model. We analyzed the effect of immigrants in the model to study the effect of immigrants for the host population. We added the following flow parameters: "the transmission between migrated and exposed class" and "the transmission between migrated and acute class." With these new features, we obtained a compartment model of six differential equations. First, we find the basic threshold quantity Ro and then find the local asymptotic stability of disease-free equilibrium and endemic equilibrium. Furthermore, we find the global stability of the disease-free and endemic equilibria. Previous similar publications have not added the kind of information about the numerical results of the model. In our case, from numerical simulation, a detailed discussion of the parameters and their numerical results is presented. We claim that with these assumptions and by adding the migrated class, the model informs policy for governments, to be aware of the immigrants and subject them to tests about the disease status. Immigrants for short visits and students should be subjected to tests to reduce the number of immigrants with disease.
CORPORATE FORESIGHT AND PERFORMANCE: A CHAIN-OF-EFFECTS MODEL
DEFF Research Database (Denmark)
Jissink, Tymen; Huizingh, Eelko K.R.E.; Rohrbeck, René
2015-01-01
, formal organization, and culture. We investigate the relation of corporate foresight with three innovation performance dimensions – new product success, new product innovativeness, and financial performance. We use partial-least-squares structural equations modelling to assess our measurement mode ls......In this paper we develop and validate a measurement scale for corporate foresight and examine its impact on performance in a chain-of-effects model. We conceptualize corporate foresight as an organizational ability consisting of five distinct dimensions: information scope, method usage, people...... and test our research hypotheses. Using a cross-industry sample of 153 innovative firms, we find that corporate foresight can be validly and reliably measured by our measurement instrument. The results of the structural model support the hypothesized positive effects of corporate foresight on all...
Study of a model equation in detonation theory: multidimensional effects
Faria, Luiz M; Rosales, Rodolfo R
2015-01-01
We extend the reactive Burgers equation presented in Kasimov et al. Phys. Rev. Lett., 110 (2013) and Faria et al. SIAM J. Appl. Maths, 74 (2014), to include multidimensional effects. Furthermore, we explain how the model can be rationally justified following the ideas of the asymptotic theory developed in Faria et al. JFM (2015). The proposed model is a forced version of the unsteady small disturbance transonic flow equations. We show that for physically reasonable choices of forcing functions, traveling wave solutions akin to detonation waves exist. It is demonstrated that multidimensional effects play an important role in the stability and dynamics of the traveling waves. Numerical simulations indicate that solutions of the model tend to form multi-dimensional patterns analogous to cells in gaseous detonations.
REGRESSION ANALYSIS OF PRODUCTIVITY USING MIXED EFFECT MODEL
Directory of Open Access Journals (Sweden)
Siana Halim
2007-01-01
Full Text Available Production plants of a company are located in several areas that spread across Middle and East Java. As the production process employs mostly manpower, we suspected that each location has different characteristics affecting the productivity. Thus, the production data may have a spatial and hierarchical structure. For fitting a linear regression using the ordinary techniques, we are required to make some assumptions about the nature of the residuals i.e. independent, identically and normally distributed. However, these assumptions were rarely fulfilled especially for data that have a spatial and hierarchical structure. We worked out the problem using mixed effect model. This paper discusses the model construction of productivity and several characteristics in the production line by taking location as a random effect. The simple model with high utility that satisfies the necessary regression assumptions was built using a free statistic software R version 2.6.1.
Nonextensive critical effects in the Nambu--Jona-Lasinio model
Rozynek, Jacek
2009-01-01
The critical phenomena in strongly interaction matter are generally investigated using the mean-field model and are characterized by well defined critical exponents. However, such models provide only average properties of the corresponding order parameters and neglect altogether their possible fluctuations. Also the possible long range effect are neglected in the mean field approach. Here we investigate the critical behavior in the nonextensive version of the Nambu Jona-Lasinio model (NJL). It allows to account for such effects in a phenomenological way by means of a single parameter $q$, the nonextensivity parameter. In particular, we show how the nonextensive statistics influence the region of the critical temperature and chemical potential in the NJL mean field approach.
Multivariate parametric random effect regression models for fecundability studies.
Ecochard, R; Clayton, D G
2000-12-01
Delay until conception is generally described by a mixture of geometric distributions. Weinberg and Gladen (1986, Biometrics 42, 547-560) proposed a regression generalization of the beta-geometric mixture model where covariates effects were expressed in terms of contrasts of marginal hazards. Scheike and Jensen (1997, Biometrics 53, 318-329) developed a frailty model for discrete event times data based on discrete-time analogues of Hougaard's results (1984, Biometrika 71, 75-83). This paper is on a generalization to a three-parameter family distribution and an extension to multivariate cases. The model allows the introduction of explanatory variables, including time-dependent variables at the subject-specific level, together with a choice from a flexible family of random effect distributions. This makes it possible, in the context of medically assisted conception, to include data sources with multiple pregnancies (or attempts at pregnancy) per couple.
Estimation of Nonlinear Dynamic Panel Data Models with Individual Effects
Directory of Open Access Journals (Sweden)
Yi Hu
2014-01-01
Full Text Available This paper suggests a generalized method of moments (GMM based estimation for dynamic panel data models with individual specific fixed effects and threshold effects simultaneously. We extend Hansen’s (Hansen, 1999 original setup to models including endogenous regressors, specifically, lagged dependent variables. To address the problem of endogeneity of these nonlinear dynamic panel data models, we prove that the orthogonality conditions proposed by Arellano and Bond (1991 are valid. The threshold and slope parameters are estimated by GMM, and asymptotic distribution of the slope parameters is derived. Finite sample performance of the estimation is investigated through Monte Carlo simulations. It shows that the threshold and slope parameter can be estimated accurately and also the finite sample distribution of slope parameters is well approximated by the asymptotic distribution.
Ecotoxicity Effect Indicator for use in the OMNIITOX Base Model
DEFF Research Database (Denmark)
Larsen, Henrik Fred; Payet, Jerome; Molander, S
2004-01-01
The ecotoxicity effect indicator (EFI) is used together with the input results from the fate modelling when calculating characterisation factors for ecotoxicity within life-cycle impact assessment (LCIA). A number of methods have been proposed and used in recent years involving different approaches...... focusing on their statistical robustness. Considerations about the possibility to relate the effect indicator to damage on the endpoint, the ecosystem, are also included. The effect-based approaches are tested for their robustness in estimating an HC50 in a practical test on datasets from eleven different...
The effect of uncertainty and systematic errors in hydrological modelling
Steinsland, I.; Engeland, K.; Johansen, S. S.; Øverleir-Petersen, A.; Kolberg, S. A.
2014-12-01
The aims of hydrological model identification and calibration are to find the best possible set of process parametrization and parameter values that transform inputs (e.g. precipitation and temperature) to outputs (e.g. streamflow). These models enable us to make predictions of streamflow. Several sources of uncertainties have the potential to hamper the possibility of a robust model calibration and identification. In order to grasp the interaction between model parameters, inputs and streamflow, it is important to account for both systematic and random errors in inputs (e.g. precipitation and temperatures) and streamflows. By random errors we mean errors that are independent from time step to time step whereas by systematic errors we mean errors that persists for a longer period. Both random and systematic errors are important in the observation and interpolation of precipitation and temperature inputs. Important random errors comes from the measurements themselves and from the network of gauges. Important systematic errors originate from the under-catch in precipitation gauges and from unknown spatial trends that are approximated in the interpolation. For streamflow observations, the water level recordings might give random errors whereas the rating curve contributes mainly with a systematic error. In this study we want to answer the question "What is the effect of random and systematic errors in inputs and observed streamflow on estimated model parameters and streamflow predictions?". To answer we test systematically the effect of including uncertainties in inputs and streamflow during model calibration and simulation in distributed HBV model operating on daily time steps for the Osali catchment in Norway. The case study is based on observations from, uncertainty carefullt quantified, and increased uncertainties and systmatical errors are done realistically by for example removing a precipitation gauge from the network.We find that the systematical errors in
Generalized effective medium resistivity model for low resistivity reservoir
Institute of Scientific and Technical Information of China (English)
2008-01-01
With the advancement in oil exploration,producible oil and gas are being found in low resistivity reservoirs,which may otherwise be erroneously thought as water zones from their resistivity.However,the evaluation of low resistivity reservoirs remains difficult from log interpretation.Since low resistivity in hydrocarbon bearing sands can be caused by dispersed clay,laminated shale,conductive matrix grains,microscopic capillary pores and high saline water,a new resistivity model is required for more accurate hydrocarbon saturation prediction for low resistivity formations.Herein,a generalized effective medium resistivity model has been proposed for low resistivity reservoirs,based on experimental measurements on artificial low resistivity shaly sand samples,symmetrical anisotropic effective medium theory for resistivity interpretations,and geneses and conductance mechanisms of low resistivity reservoirs.By analyzing effects of some factors on the proposed model,we show theoretically the model can describe conductance mechanisms of low resistivity reservoirs with five geneses.Also,shale distribution largely affects water saturation predicted by the model.Resistivity index decreases as fraction and conductivity of laminated shale,or fraction of dispersed clay,or conductivity of rock matrix grains increases.Resistivity index decreases as matrix percolation exponent,or percolation rate of capillary bound water increases,and as percolation exponent of capillary bound water,or matrix percolation rate,or free water percolation rate decreases.Rock sample data from low resistivity reservoirs with different geneses and interpretation results for log data show that the proposed model can be applied in low resistivity reservoirs containing high salinity water,dispersed clay,microscopic capillary pores,laminated shale and conductive matrix grains,and thus is considered as a generalized resistivity model for low resistivity reservoir evaluation.
Generalized effective medium resistivity model for low resistivity reservoir
Institute of Scientific and Technical Information of China (English)
SONG YanJie; TANG XiaoMin
2008-01-01
With the advancement in oil exploration, producible oil and gas are being found in low resistivity reservoirs, which may otherwise be erroneously thought as water zones from their resistivity. However,the evaluation of low resistivity reservoirs remains difficult from log interpretation. Since low resistivity in hydrocarbon bearing sands can be caused by dispersed clay, laminated shale, conductive matrix grains, microscopic capillary pores and high saline water, a new resistivity model is required for more accurate hydrocarbon saturation prediction for low resistivity formations. Herein, a generalized effective medium resistivity model has been proposed for low resistivity reservoirs, based on experimental measurements on artificial low resistivity shaly sand samples, symmetrical anisotropic effective medium theory for resistivity interpretations, and geneses and conductance mechanisms of low resistivity reservoirs. By analyzing effects of some factors on the proposed model, we show theoretically the model can describe conductance mechanisms of low resistivity reservoirs with five geneses. Also,shale distribution largely affects water saturation predicted by the model. Resistivity index decreases as fraction and conductivity of laminated shale, or fraction of dispersed clay, or conductivity of rock matrix grains increases. Resistivity index decreases as matrix percolation exponent, or percolation rate of capillary bound water increases, and as percolation exponent of capillary bound water, or matrix percolation rate, or free water percolation rate decreases. Rock sample data from low resistivity reservoirs with different geneses and interpretation results for log data show that the proposed model can be applied in low resistivity reservoirs containing high salinity water, dispersed clay, microscopic capillary pores, laminated shale and conductive matrix grains, and thus is considered as a generalized resistivity model for low resistivity reservoir evaluation.
Global Dynamics of Avian Influenza Epidemic Models with Psychological Effect
Directory of Open Access Journals (Sweden)
Sanhong Liu
2015-01-01
Full Text Available Cross-sectional surveys conducted in Thailand and China after the outbreaks of the avian influenza A H5N1 and H7N9 viruses show a high degree of awareness of human avian influenza in both urban and rural populations, a higher level of proper hygienic practice among urban residents, and in particular a dramatically reduced number of visits to live markets in urban population after the influenza A H7N9 outbreak in China in 2013. In this paper, taking into account the psychological effect toward avian influenza in the human population, a bird-to-human transmission model in which the avian population exhibits saturation effect is constructed. The dynamical behavior of the model is studied by using the basic reproduction number. The results demonstrate that the saturation effect within avian population and the psychological effect in human population cannot change the stability of equilibria but can affect the number of infected humans if the disease is prevalent. Numerical simulations are given to support the theoretical results and sensitivity analyses of the basic reproduction number in terms of model parameters that are performed to seek for effective control measures for avian influenza.
Circuit models and SPICE macro-models for quantum Hall effect devices
Ortolano, Massimo
2015-01-01
Quantum Hall effect (QHE) devices are a pillar of modern quantum electrical metrology. Electrical networks including one or more QHE elements can be used as quantum resistance and impedance standards. The analysis of these networks allows metrologists to evaluate the effect of the inevitable parasitic parameters on their performance as standards. This paper presents a systematic analysis of the various circuit models for QHE elements proposed in the literature, and the development of a new model. This last model is particularly suited to be employed with the analogue electronic circuit simulator SPICE. The SPICE macro-model and examples of SPICE simulations, validated by comparison with the corresponding analytical solution and/or experimental data, are provided.
Effective Thermal Conductivity Modeling of Sandstones: SVM Framework Analysis
Rostami, Alireza; Masoudi, Mohammad; Ghaderi-Ardakani, Alireza; Arabloo, Milad; Amani, Mahmood
2016-06-01
Among the most significant physical characteristics of porous media, the effective thermal conductivity (ETC) is used for estimating the thermal enhanced oil recovery process efficiency, hydrocarbon reservoir thermal design, and numerical simulation. This paper reports the implementation of an innovative least square support vector machine (LS-SVM) algorithm for the development of enhanced model capable of predicting the ETCs of dry sandstones. By means of several statistical parameters, the validity of the presented model was evaluated. The prediction of the developed model for determining the ETCs of dry sandstones was in excellent agreement with the reported data with a coefficient of determination value ({R}2) of 0.983 and an average absolute relative deviation of 0.35 %. Results from present research show that the proposed LS-SVM model is robust, reliable, and efficient in calculating the ETCs of sandstones.
Modeling of Drift Effects on Solar Tower Concentrated Flux Distributions
Directory of Open Access Journals (Sweden)
Luis O. Lara-Cerecedo
2016-01-01
Full Text Available A novel modeling tool for calculation of central receiver concentrated flux distributions is presented, which takes into account drift effects. This tool is based on a drift model that includes different geometrical error sources in a rigorous manner and on a simple analytic approximation for the individual flux distribution of a heliostat. The model is applied to a group of heliostats of a real field to obtain the resulting flux distribution and its variation along the day. The distributions differ strongly from those obtained assuming the ideal case without drift or a case with a Gaussian tracking error function. The time evolution of peak flux is also calculated to demonstrate the capabilities of the model. The evolution of this parameter also shows strong differences in comparison to the case without drift.
CRLH Transmission Lines for Telecommunications: Fast and Effective Modeling
Directory of Open Access Journals (Sweden)
Juanjuan Gao
2017-01-01
Full Text Available A different parameter extraction approach based on zero immittances for composite right/left-handed (CRLH structure is presented. For lossless unit cell equivalent circuit model, LC parameters of series and parallel branches are extracted according to series resonance frequency and parallel resonance frequency, respectively. This approach can be applied to symmetric and unbalanced CRLH structures. The parameter extraction procedure is provided and validated by T-type unit cell model. The responses of distributed prototype and extracted equivalent LC circuit model are in good agreement. The equivalent circuit modeling can improve the degree of freedom in the CRLH TLs design. This parameter extraction method provides an effective and straightforward way in CRLH metamaterials design and applications in telecommunication systems.
Effective Q-Q Interactions in Constituent Quark Models
Glozman, L Ya; Plessas, W; Varga, K; Wagenbrun, R F
1998-01-01
We study the performance of some recent potential models suggested as effective interactions between constituent quarks. In particular, we address constituent quark models for baryons with hybrid Q-Q interactions stemming from one-gluon plus meson exchanges. Upon recalculating two of such models we find them to fail in describing the N and \\Delta spectra. Our calculations are based on accurate solutions of the three-quark systems in both a variational Schrödinger and a rigorous Faddeev approach. It is argued that hybrid {Q-Q} interactions encounter difficulties in describing baryon spectra due to the specific contributions from one-gluon and pion exchanges together. In contrast, a chiral constituent quark model with a Q-Q interaction solely derived from Goldstone-boson exchange is capable of providing a unified description of both the N and \\Delta spectra in good agreement with phenomenology.
Comparative assessment of PV plant performance models considering climate effects
DEFF Research Database (Denmark)
Tina, Giuseppe; Ventura, Cristina; Sera, Dezso
2017-01-01
The paper investigates the effect of climate conditions on the accuracy of PV system performance models (physical and interpolation methods) which are used within a monitoring system as a reference for the power produced by a PV system to detect inefficient or faulty operating conditions....... The methodological approach is based on comparative tests of the analyzed models applied to two PV plants installed respectively in north of Denmark (Aalborg) and in the south of Italy (Agrigento). The different ambient, operating and installation conditions allow to understand how these factors impact the precision...... and effectiveness of such approaches, among these factors it is worth mentioning the different percentage of diffuse component of the yearly solar radiation on the global one. The experimental results show the effectiveness of the proposed approach. In order to have the possibility to analyze and compare...
Multiple flux difference effect in the lattice hydrodynamic model
Institute of Scientific and Technical Information of China (English)
Wang Tao; Gao Zi-You; Zhao Xiao-Mei
2012-01-01
Considering the effect of multiple flux difference,an extended lattice model is proposed to improve the stability of traffic flow.The stability condition of the new model is obtained by using linear stability theory.The theoretical analysis result shows that considering the flux difference effect ahead can stabilize traffic flow.The nonlinear analysis is also conducted by using a reductive perturbation method.The modified KdV (mKdV) equation near the critical point is derived and the kink-antikink solution is obtained from the mKdV equation.Numerical simulation results show that the multiple flux difference effect can suppress the traffic jam considerably,which is in line with the analytical result.
Modelling turbulent stellar convection zones: sub-grid scales effects
Strugarek, A; Brun, A S; Charbonneau, P; Mathis, S; Smolarkiewicz, P K
2016-01-01
The impressive development of global numerical simulations of turbulent stellar interiors unveiled a variety of possible differential rotation (solar or anti-solar), meridional circulation (single or multi-cellular), and dynamo states (stable large scale toroidal field or periodically reversing magnetic fields). Various numerical schemes, based on the so-called anelastic set of equations, were used to obtain these results. It appears today mandatory to assess their robustness with respect to the details of the numerics, and in particular to the treatment of turbulent sub-grid scales. We report on an ongoing comparison between two global models, the ASH and EULAG codes. In EULAG the sub-grid scales are treated implicitly by the numerical scheme, while in ASH their effect is generally modelled by using enhanced dissipation coefficients. We characterize the sub-grid scales effect in a turbulent convection simulation with EULAG. We assess their effect at each resolved scale with a detailed energy budget. We deriv...
The Effects of SIRT1 on Alzheimer's Disease Models
Directory of Open Access Journals (Sweden)
Gizem Donmez
2012-01-01
Full Text Available Sirtuins are highly conserved NAD+-dependent enzymes that were shown to have beneficial effects against age-related diseases. Aging is the major risk factor for all neurodegenerative disorders including Alzheimer’s Disease (AD. Sirtuins have been widely studied in the context of AD using different mouse models. In most of these studies, overexpression of SIRT1 has been shown to have protective effects against AD. Therefore, designing therapeutics based on increasing SIRT1 activity might be important for investigating the ways of treatment for this disease. This paper summarizes the recent research on the effect of SIRT1 in AD animal models and also the potential of SIRT1 being a therapeutical target for AD.
Effective constraint potential in lattice Weinberg - Salam model
Polikarpov, M I
2011-01-01
We investigate lattice Weinberg - Salam model without fermions for the value of the Weinberg angle $\\theta_W \\sim 30^o$, and bare fine structure constant around $\\alpha \\sim 1/150$. We consider the value of the scalar self coupling corresponding to bare Higgs mass around 150 GeV. The effective constraint potential for the zero momentum scalar field is used in order to investigate phenomena existing in the vicinity of the phase transition between the physical Higgs phase and the unphysical symmetric phase of the lattice model. This is the region of the phase diagram, where the continuum physics is to be approached. We compare the above mentioned effective potential (calculated in selected gauges) with the effective potential for the value of the scalar field at a fixed space - time point. We also calculate the renormalized fine structure constant using the correlator of Polyakov lines and compare it with the one - loop perturbative estimate.
Simple computer model for the quantum Zeno effect
Wallace, D
2000-01-01
This paper presents a simple model for repeated measurement of a quantum system: the evolution of a free particle, simulated by discretising the particle's position. This model is easily simulated by computer and provides a useful arena to investigate the effects of measurement upon dynamics, in particular the slowing of evolution due to measurement (the `quantum Zeno effect'). The results of this simulation are discussed for two rather different sorts of measurement process, both of which are (simplified forms of) measurements used in previous simulations of position measurement. A number of interesting results due to measurement are found, and the investigation casts some light on previous disagreements about the presence or absence of the Zeno effect.
Effective Transparency: A Test of Atomistic Laser-Cluster Models
Pandit, Rishi; Teague, Thomas; Hartwick, Zachary; Bigaouette, Nicolas; Ramunno, Lora; Ackad, Edward
2016-01-01
The effective transparency of rare-gas clusters, post-interaction with an extreme ultraviolet (XUV) pump pulse, is studied by using an atomistic hybrid quantum-classical molecular dynamics model. We find there is an intensity range in which an XUV probe pulse has no lasting effect on the average charge state of a cluster after being saturated by an XUV pump pulse: the cluster is effectively transparent to the probe pulse. The range of this phenomena increases with the size of the cluster and thus provides an excellent candidate for an experimental test of the effective transparency effect. We present predictions for the clusters at the peak of the laser pulse as well as the experimental time-of-flight signal expected along with trends which can be compared with. Significant deviations from these predictions would provide evidence for enhanced photoionization mechanism(s).
Roe, Byron
2013-01-01
The effect of correlations between model parameters and nuisance parameters is discussed, in the context of fitting model parameters to data. Modifications to the usual $\\chi^2$ method are required. Fake data studies, as used at present, will not be optimum. Problems will occur for applications of the Maltoni-Schwetz \\cite{ms} theorem. Neutrino oscillations are used as examples, but the problems discussed here are general ones, which are often not addressed.
Effective-field-theory model for the fractional quantum Hall effect
Zhang, S. C.; Hansson, T. H.; Kivelson, S.
1989-01-01
Starting directly from the microscopic Hamiltonian, a field-theory model is derived for the fractional quantum Hall effect. By considering an approximate coarse-grained version of the same model, a Landau-Ginzburg theory similar to that of Girvin (1986) is constructed. The partition function of the model exhibits cusps as a function of density. It is shown that the collective density fluctuations are massive.
Estes, Jason P; Nguyen, Danh V; Dalrymple, Lorien S; Mu, Yi; Şentürk, Damla
2016-05-20
Recent studies found that infection-related hospitalization was associated with increased risk of cardiovascular (CV) events, such as myocardial infarction and stroke in the dialysis population. In this work, we develop time-varying effects modeling tools in order to examine the CV outcome risk trajectories during the time periods before and after an initial infection-related hospitalization. For this, we propose partly conditional and fully conditional partially linear generalized varying coefficient models (PL-GVCMs) for modeling time-varying effects in longitudinal data with substantial follow-up truncation by death. Unconditional models that implicitly target an immortal population is not a relevant target of inference in applications involving a population with high mortality, like the dialysis population. A partly conditional model characterizes the outcome trajectory for the dynamic cohort of survivors, where each point in the longitudinal trajectory represents a snapshot of the population relationships among subjects who are alive at that time point. In contrast, a fully conditional approach models the time-varying effects of the population stratified by the actual time of death, where the mean response characterizes individual trends in each cohort stratum. We compare and contrast partly and fully conditional PL-GVCMs in our aforementioned application using hospitalization data from the United States Renal Data System. For inference, we develop generalized likelihood ratio tests. Simulation studies examine the efficacy of estimation and inference procedures.
Grajeda, Laura M; Ivanescu, Andrada; Saito, Mayuko; Crainiceanu, Ciprian; Jaganath, Devan; Gilman, Robert H; Crabtree, Jean E; Kelleher, Dermott; Cabrera, Lilia; Cama, Vitaliano; Checkley, William
2016-01-01
Childhood growth is a cornerstone of pediatric research. Statistical models need to consider individual trajectories to adequately describe growth outcomes. Specifically, well-defined longitudinal models are essential to characterize both population and subject-specific growth. Linear mixed-effect models with cubic regression splines can account for the nonlinearity of growth curves and provide reasonable estimators of population and subject-specific growth, velocity and acceleration. We provide a stepwise approach that builds from simple to complex models, and account for the intrinsic complexity of the data. We start with standard cubic splines regression models and build up to a model that includes subject-specific random intercepts and slopes and residual autocorrelation. We then compared cubic regression splines vis-à-vis linear piecewise splines, and with varying number of knots and positions. Statistical code is provided to ensure reproducibility and improve dissemination of methods. Models are applied to longitudinal height measurements in a cohort of 215 Peruvian children followed from birth until their fourth year of life. Unexplained variability, as measured by the variance of the regression model, was reduced from 7.34 when using ordinary least squares to 0.81 (p linear mixed-effect models with random slopes and a first order continuous autoregressive error term. There was substantial heterogeneity in both the intercept (p linear regression equation for both estimation and prediction of population- and individual-level growth in height. We show that cubic regression splines are superior to linear regression splines for the case of a small number of knots in both estimation and prediction with the full linear mixed effect model (AIC 19,352 vs. 19,598, respectively). While the regression parameters are more complex to interpret in the former, we argue that inference for any problem depends more on the estimated curve or differences in curves rather
Modelling the effect of telegraph noise in the SIRS epidemic model using Markovian switching
Greenhalgh, D.; Liang, Y.; Mao, X.
2016-11-01
We discuss the effect of introducing telegraph noise, which is an example of an environmental noise, into the susceptible-infectious-recovered-susceptible (SIRS) model by examining the model using a finite-state Markov Chain (MC). First we start with a two-state MC and show that there exists a unique nonnegative solution and establish the conditions for extinction and persistence. We then explain how the results can be generalised to a finite-state MC. The results for the SIR (Susceptible-Infectious-Removed) model with Markovian Switching (MS) are a special case. Numerical simulations are produced to confirm our theoretical results.
New calculations in Dirac gaugino models: operators, expansions, and effects
Carpenter, Linda M.; Goodman, Jessica
2015-07-01
In this work we calculate important one loop SUSY-breaking parameters in models with Dirac gauginos, which are implied by the existence of heavy messenger fields. We find that these SUSY-breaking effects are all related by a small number of parameters, thus the general theory is tightly predictive. In order to make the most accurate analyses of one loop effects, we introduce calculations using an expansion in SUSY breaking messenger mass, rather than relying on postulating the forms of effective operators. We use this expansion to calculate one loop contributions to gaugino masses, non-holomorphic SM adjoint masses, new A-like and B-like terms, and linear terms. We also test the Higgs potential in such models, and calculate one loop contributions to the Higgs mass in certain limits of R-symmetric models, finding a very large contribution in many regions of the [InlineMediaObject not available: see fulltext.], where Higgs fields couple to standard model adjoint fields.
Modelling the effect of shear strength on isentropic compression experiments
Thomson, Stuart; Howell, Peter; Ockendon, John; Ockendon, Hilary
2017-01-01
Isentropic compression experiments (ICE) are a way of obtaining equation of state information for metals undergoing violent plastic deformation. In a typical experiment, millimetre thick metal samples are subjected to pressures on the order of 10 - 102 GPa, while the yield strength of the material can be as low as 10-2 GPa. The analysis of such experiments has so far neglected the effect of shear strength, instead treating the highly plasticised metal as an inviscid compressible fluid. However making this approximation belies the basic elastic nature of a solid object. A more accurate method should strive to incorporate the small but measurable effects of shear strength. Here we present a one-dimensional mathematical model for elastoplasticity at high stress which allows for both compressibility and the shear strength of the material. In the limit of zero yield stress this model reproduces the hydrodynamic models currently used to analyse ICEs. Numerical solutions of the governing equations will then be presented for problems relevant to ICEs in order to investigate the effects of shear strength compared with a model based purely on hydrodynamics.
A model to evaluate quality and effectiveness of disease management.
Lemmens, K M M; Nieboer, A P; van Schayck, C P; Asin, J D; Huijsman, R
2008-12-01
Disease management has emerged as a new strategy to enhance quality of care for patients suffering from chronic conditions, and to control healthcare costs. So far, however, the effects of this strategy remain unclear. Although current models define the concept of disease management, they do not provide a systematic development or an explanatory theory of how disease management affects the outcomes of care. The objective of this paper is to present a framework for valid evaluation of disease-management initiatives. The evaluation model is built on two pillars of disease management: patient-related and professional-directed interventions. The effectiveness of these interventions is thought to be affected by the organisational design of the healthcare system. Disease management requires a multifaceted approach; hence disease-management programme evaluations should focus on the effects of multiple interventions, namely patient-related, professional-directed and organisational interventions. The framework has been built upon the conceptualisation of these disease-management interventions. Analysis of the underlying mechanisms of these interventions revealed that learning and behavioural theories support the core assumptions of disease management. The evaluation model can be used to identify the components of disease-management programmes and the mechanisms behind them, making valid comparison feasible. In addition, this model links the programme interventions to indicators that can be used to evaluate the disease-management programme. Consistent use of this framework will enable comparisons among disease-management programmes and outcomes in evaluation research.
Schmidt, Patricia; Hannam, Mark
2014-01-01
Gravitational waves (GWs) emitted by generic black-hole binaries show a rich structure that directly reflects the complex dynamics introduced by the precession of the orbital plane, which poses a real challenge to the development of generic waveform models. Recent progress in modelling these signals relies on an approximate decoupling between the non-precessing secular inspiral and a precession-induced rotation. However, the latter depends in general on all physical parameters of the binary which makes modelling efforts as well as understanding parameter-estimation prospects prohibitively complex. Here we show that the dominant precession effects can be captured by a reduced set of spin parameters. Specifically, we introduce a single \\emph{effective precession spin} parameter, $\\chi_p$, which is defined from the spin components that lie in the orbital plane at some (arbitrary) instant during the inspiral. We test the efficacy of this parameter by considering binary inspiral configurations specified by the phy...
Boron doped simulated graphene field effect transistor model
Sharma, Preetika; Kaur, Inderpreet; Gupta, Shuchi; Singh, Sukhbir
2016-05-01
Graphene based electronic devices due to its unique properties has transformed electronics. A Graphene Field Effect Transistor (GNRFET) model is simulated in Virtual Nano Lab (VNL) and the calculations are based on density functional theory (DFT). Simulations were performed on this pristine GNRFET model and the transmission spectrum was observed. The graph obtained showed a uniform energy gap of +1 to -1eV and the highest transmission peak at -1.75 eV. To this pristine model of GNRFET, doping was introduced and its effect was seen on the Fermi level obtained in the transmission spectrum. Boron as a dopant was used which showed variations in both the transmission peaks and the energy gap. In this model, first the single boron was substituted in place of carbon and Fermi level showed an energy gap of 1.5 to -0.5eV with the highest transmission peak at -1.3 eV. In another variation in the model, two carbon atoms were replaced by two boron atoms and Fermi level shifted from 2 to 0.25eV. In this observation, the highest transmission peak was observed at -1(approx.). The use of nanoelectronic devices have opened many areas of applications as GFET is an excellent building block for electronic circuits, and is being used in applications such as high-performance frequency doublers and mixers, digital modulators, phase detectors, optoelectronics and spintronics.
Modelling of single bubble-dynamics and thermal effects
Papoulias, D.; Gavaises, M.
2015-12-01
This paper evaluates the solution effects of different Rayleigh-Plesset models (R-P) for simulating the growth/collapse dynamics and thermal behaviour of homogeneous gas bubbles. The flow inputs used for the discrete cavitation bubble calculations are obtained from Reynolds-averaged Navier-Stokes simulations (RANS), performed in high-pressure nozzle holes. Parametric 1-D results are presented for the classical thermal R-P equation [1] as well as for refined models which incorporated compressibility corrections and thermal effects [2, 3]. The thermal bubble model is coupled with the energy equation, which provides the temperature of the bubble as a function of conduction/convection and radiation heat-transfer mechanisms. For approximating gas pressure variations a high-order virial equation of state (EOS) was used, based on Helmholtz free energy principle [4]. The coded thermal R-P model was validated against experimental measurements [5] and model predictions [6] reported in single-bubble sonoluminescence (SBSL).
Directory of Open Access Journals (Sweden)
Shashikant Mishra
2011-01-01
Full Text Available Objective: We performed a comparative study of high-fidelity training models for flexible ureteroscopy (URS. Our objective was to determine whether high-fidelity non-virtual reality (VR models are as effective as the VR model in teaching flexible URS skills. Materials and Methods: Twenty-one trained urologists without clinical experience of flexible URS underwent dry lab simulation practice. After a warm-up period of 2 h, tasks were performed on a high-fidelity non-VR (Uro-scopic Trainer TM ; Endo-Urologie-Modell TM and a high-fidelity VR model (URO Mentor TM . The participants were divided equally into three batches with rotation on each of the three stations for 30 min. Performance of the trainees was evaluated by an expert ureteroscopist using pass rating and global rating score (GRS. The participants rated a face validity questionnaire at the end of each session. Results: The GRS improved statistically at evaluation performed after second rotation (P<0.001 for batches 1, 2 and 3. Pass ratings also improved significantly for all training models when the third and first rotations were compared (P<0.05. The batch that was trained on the VR-based model had more improvement on pass ratings on second rotation but could not achieve statistical significance. Most of the realistic domains were higher for a VR model as compared with the non-VR model, except the realism of the flexible endoscope. Conclusions: All the models used for training flexible URS were effective in increasing the GRS and pass ratings irrespective of the VR status.
Modelling of structural effects on chemical reactions in turbulent flows
Energy Technology Data Exchange (ETDEWEB)
Gammelsaeter, H.R.
1997-12-31
Turbulence-chemistry interactions are analysed using algebraic moment closure for the chemical reaction term. The coupling between turbulence and chemical length and time scales generate a complex interaction process. This interaction process is called structural effects in this work. The structural effects are shown to take place on all scales between the largest scale of turbulence and the scales of the molecular motions. The set of equations describing turbulent correlations involved in turbulent reacting flows are derived. Interactions are shown schematically using interaction charts. Algebraic equations for the turbulent correlations in the reaction rate are given using the interaction charts to include the most significant couplings. In the frame of fundamental combustion physics, the structural effects appearing on the small scales of turbulence are proposed modelled using a discrete spectrum of turbulent scales. The well-known problem of averaging the Arrhenius law, the specific reaction rate, is proposed solved using a presumed single variable probability density function and a sub scale model for the reaction volume. Although some uncertainties are expected, the principles are addressed. Fast chemistry modelling is shown to be consistent in the frame of algebraic moment closure when the turbulence-chemistry interaction is accounted for in the turbulent diffusion. The modelling proposed in this thesis is compared with experimental data for an laboratory methane flame and advanced probability density function modelling. The results show promising features. Finally it is shown a comparison with full scale measurements for an industrial burner. All features of the burner are captured with the model. 41 refs., 33 figs.
Effective Orthorhombic Anisotropic Models for Wave field Extrapolation
Ibanez Jacome, Wilson
2013-05-01
Wavefield extrapolation in orthorhombic anisotropic media incorporates complicated but realistic models, to reproduce wave propagation phenomena in the Earth\\'s subsurface. Compared with the representations used for simpler symmetries, such as transversely isotropic or isotropic, orthorhombic models require an extended and more elaborated formulation that also involves more expensive computational processes. The acoustic assumption yields more efficient description of the orthorhombic wave equation that also provides a simplified representation for the orthorhombic dispersion relation. However, such representation is hampered by the sixth-order nature of the acoustic wave equation, as it also encompasses the contribution of shear waves. To reduce the computational cost of wavefield extrapolation in such media, I generate effective isotropic inhomogeneous models that are capable of reproducing the first-arrival kinematic aspects of the orthorhombic wavefield. First, in order to compute traveltimes in vertical orthorhombic media, I develop a stable, efficient and accurate algorithm based on the fast marching method. The derived orthorhombic acoustic dispersion relation, unlike the isotropic or transversely isotropic one, is represented by a sixth order polynomial equation that includes the fastest solution corresponding to outgoing P-waves in acoustic media. The effective velocity models are then computed by evaluating the traveltime gradients of the orthorhombic traveltime solution, which is done by explicitly solving the isotropic eikonal equation for the corresponding inhomogeneous isotropic velocity field. The inverted effective velocity fields are source dependent and produce equivalent first-arrival kinematic descriptions of wave propagation in orthorhombic media. I extrapolate wavefields in these isotropic effective velocity models using the more efficient isotropic operator, and the results compare well, especially kinematically, with those obtained from the
Edge effect modeling and experiments on active lap processing.
Liu, Haitao; Wu, Fan; Zeng, Zhige; Fan, Bin; Wan, Yongjian
2014-05-05
Edge effect is regarded as one of the most difficult technical issues for fabricating large primary mirrors, especially for large polishing tools. Computer controlled active lap (CCAL) uses a large size pad (e.g., 1/3 to 1/5 workpiece diameters) to grind and polish the primary mirror. Edge effect also exists in the CCAL process in our previous fabrication. In this paper the material removal rules when edge effects happen (i.e. edge tool influence functions (TIFs)) are obtained through experiments, which are carried out on a Φ1090-mm circular flat mirror with a 375-mm-diameter lap. Two methods are proposed to model the edge TIFs for CCAL. One is adopting the pressure distribution which is calculated based on the finite element analysis method. The other is building up a parametric equivalent pressure model to fit the removed material curve directly. Experimental results show that these two methods both effectively model the edge TIF of CCAL.
Modeling the prediction of business intelligence system effectiveness.
Weng, Sung-Shun; Yang, Ming-Hsien; Koo, Tian-Lih; Hsiao, Pei-I
2016-01-01
Although business intelligence (BI) technologies are continually evolving, the capability to apply BI technologies has become an indispensable resource for enterprises running in today's complex, uncertain and dynamic business environment. This study performed pioneering work by constructing models and rules for the prediction of business intelligence system effectiveness (BISE) in relation to the implementation of BI solutions. For enterprises, effectively managing critical attributes that determine BISE to develop prediction models with a set of rules for self-evaluation of the effectiveness of BI solutions is necessary to improve BI implementation and ensure its success. The main study findings identified the critical prediction indicators of BISE that are important to forecasting BI performance and highlighted five classification and prediction rules of BISE derived from decision tree structures, as well as a refined regression prediction model with four critical prediction indicators constructed by logistic regression analysis that can enable enterprises to improve BISE while effectively managing BI solution implementation and catering to academics to whom theory is important.
Modeling Effects on Forces in Shear Wall-Frame Structures
Directory of Open Access Journals (Sweden)
Adang Surahman
2015-05-01
Full Text Available Shear walls are added to a structural system to reduce lateral deformations in moment resisting frames and are designed to carry a major portion of lateral load induced by an earthquake. A small percentage error in the shear wall calculation will have a significant effect on the frame forces. The results show that even a slight difference in structural assumption, or modeling, results in significant differences. Some of these differences are beyond the values that are covered by safety factors for errors in modeling. The differences are more obvious in the upper stories. It is not recommended to overestimate shear wall stiffness, nor underestimate frame stiffness.
Effect of PLISSIT Model on Solution of Sexual Problems
Directory of Open Access Journals (Sweden)
Esra Uslu
2016-03-01
Full Text Available This systematic review study aims to determine the effect of PLISSIT model (permission, limited information, special suggestions, intensive therapy in the care of individuals having sexual problems. Two of the studies included in the systematic review have been carried out in Iran and one of them in Turkey. These studies were limited to the patients with stoma and women having sexual problems. Results presented that care via PLISSIT model improves the sexual functions and reduces sexual stress, increases the sexual desire, sexual arousal, lubrication, orgasm, sexual satisfaction and frequency of sexual activity. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(1: 52-63
Multi-Λ Hypernuclei in an Effective Hadronic Model
Institute of Scientific and Technical Information of China (English)
LIANG Yin-Hua; GUO Hua; LIU Yu-Xin
2007-01-01
@@ We extend the chiral hadronic model (FST) with an inclusion of Λ hyperon to investigate the propertiks of multi-Λ hypernuclei. With such an effective hadronic model in the relativistic mean-field approximation, we accomplish the calculations with both the conventional strong Λ-Λ interaction and the weak Λ-Λ interaction determined from recent experiment. Our calculations indicate that not only the strong but also the weak Λ-Λ interaction provide tighter binding for multi-Λ hypernuclei than the ones with only nucleons. However the strong interaction generates a binding slightly tighter than the weak interaction.
A multifluid mix model with material strength effects
Energy Technology Data Exchange (ETDEWEB)
Chang, C. H. [Los Alamos National Laboratory; Scannapieco, A. J. [Los Alamos National Laboratory
2012-04-23
We present a new multifluid mix model. Its features include material strength effects and pressure and temperature nonequilibrium between mixing materials. It is applicable to both interpenetration and demixing of immiscible fluids and diffusion of miscible fluids. The presented model exhibits the appropriate smooth transition in mathematical form as the mixture evolves from multiphase to molecular mixing, extending its applicability to the intermediate stages in which both types of mixing are present. Virtual mass force and momentum exchange have been generalized for heterogeneous multimaterial mixtures. The compression work has been extended so that the resulting species energy equations are consistent with the pressure force and material strength.
Effective Charge on Polymer Colloids Obtained Using a Renormalization Model.
Quesada-Pérez; Callejas-Fernández; Hidalgo-Álvarez
1998-10-01
Static light scattering has been used to study the electrostatic interaction between colloidal particles. Experiments were carried out using a latex with a very small diameter, allowing structure determination at high particle concentration. The obtained effective charge characterizing this interaction is found to be smaller than the bare charge determined from titration. A renormalization model connecting both values has been used. The agreement between the renormalized charge and that obtained from scattering data seems to point out that this model operates well. Copyright 1998 Academic Press.
A Model for Effective Professional Development of Formal Science Educators
Bleacher, L. V.; Jones, A. J. P.; Farrell, W. M.
2015-01-01
The Lunar Workshops for Educators (LWE) series was developed by the Lunar Reconnaissance Orbiter (LRO) education team in 2010 to provide professional development on lunar science and exploration concepts for grades 6-9 science teachers. Over 300 educators have been trained to date. The LWE model incorporates best practices from pedagogical research of science education, thoughtful integration of scientists and engineer subject matter experts for both content presentations and informal networking with educators, access to NASA-unique facilities, hands-on and data-rich activities aligned with education standards, exposure to the practice of science, tools for addressing common misconceptions, follow-up with participants, and extensive evaluation. Evaluation of the LWE model via pre- and post-assessments, daily workshop surveys, and follow-up surveys at 6-month and 1-year intervals indicate that the LWE are extremely effective in increasing educators' content knowledge, confidence in incorporating content into the classroom, understanding of the practice of science, and ability to address common student misconceptions. In order to address the efficacy of the LWE model for other science content areas, the Dynamic Response of Environments at Asteroids, the Moon, and moons of Mars (DREAM2) education team, funded by NASA's Solar System Exploration Research Virtual Institute, developed and ran a pilot workshop called Dream2Explore at NASA's Goddard Space Flight Center in June, 2015. Dream2Explore utilized the LWE model, but incorporated content related to the science and exploration of asteroids and the moons of Mars. Evaluation results indicate that the LWE model was effectively used for educator professional development on non-lunar content. We will present more detail on the LWE model, evaluation results from the Dream2Explore pilot workshop, and suggestions for the application of the model with other science content for robust educator professional development.
Development and validation of a tokamak skin effect transformer model
Romero, J. A.; Moret, J.-M.; Coda, S.; Felici, F.; Garrido, I.
2012-02-01
A lumped parameter, state space model for a tokamak transformer including the slow flux penetration in the plasma (skin effect transformer model) is presented. The model does not require detailed or explicit information about plasma profiles or geometry. Instead, this information is lumped in system variables, parameters and inputs. The model has an exact mathematical structure built from energy and flux conservation theorems, predicting the evolution and non-linear interaction of plasma current and internal inductance as functions of the primary coil currents, plasma resistance, non-inductive current drive and the loop voltage at a specific location inside the plasma (equilibrium loop voltage). Loop voltage profile in the plasma is substituted by a three-point discretization, and ordinary differential equations are used to predict the equilibrium loop voltage as a function of the boundary and resistive loop voltages. This provides a model for equilibrium loop voltage evolution, which is reminiscent of the skin effect. The order and parameters of this differential equation are determined empirically using system identification techniques. Fast plasma current modulation experiments with random binary signals have been conducted in the TCV tokamak to generate the required data for the analysis. Plasma current was modulated under ohmic conditions between 200 and 300 kA with 30 ms rise time, several times faster than its time constant L/R ≈ 200 ms. A second-order linear differential equation for equilibrium loop voltage is sufficient to describe the plasma current and internal inductance modulation with 70% and 38% fit parameters, respectively. The model explains the most salient features of the plasma current transients, such as the inverse correlation between plasma current ramp rates and internal inductance changes, without requiring detailed or explicit information about resistivity profiles. This proves that a lumped parameter modelling approach can be used to
A Model for Effective Professional Development of Formal Science Educators
Bleacher, L.; Jones, A. P.; Farrell, W. M.
2015-12-01
The Lunar Workshops for Educators (LWE) series was developed by the Lunar Reconnaissance Orbiter (LRO) education team in 2010 to provide professional development on lunar science and exploration concepts for grades 6-9 science teachers. Over 300 educators have been trained to date. The LWE model incorporates best practices from pedagogical research of science education, thoughtful integration of scientists and engineer subject matter experts for both content presentations and informal networking with educators, access to NASA-unique facilities, hands-on and data-rich activities aligned with education standards, exposure to the practice of science, tools for addressing common misconceptions, follow-up with participants, and extensive evaluation. Evaluation of the LWE model via pre- and post-assessments, daily workshop surveys, and follow-up surveys at 6-month and 1-year intervals indicate that the LWE are extremely effective in increasing educators' content knowledge, confidence in incorporating content into the classroom, understanding of the practice of science, and ability to address common student misconceptions. In order to address the efficacy of the LWE model for other science content areas, the Dynamic Response of Environments at Asteroids, the Moon, and moons of Mars (DREAM2) education team, funded by NASA's Solar System Exploration Research Virtual Institute, developed and ran a pilot workshop called Dream2Explore at NASA's Goddard Space Flight Center in June, 2015. Dream2Explore utilized the LWE model, but incorporated content related to the science and exploration of asteroids and the moons of Mars. Evaluation results indicate that the LWE model was effectively used for educator professional development on non-lunar content. We will present more detail on the LWE model, evaluation results from the Dream2Explore pilot workshop, and suggestions for the application of the model with other science content for robust educator professional development.
GCR Environmental Models III: GCR Model Validation and Propagated Uncertainties in Effective Dose
Slaba, Tony C.; Xu, Xiaojing; Blattnig, Steve R.; Norman, Ryan B.
2014-01-01
This is the last of three papers focused on quantifying the uncertainty associated with galactic cosmic rays (GCR) models used for space radiation shielding applications. In the first paper, it was found that GCR ions with Z>2 and boundary energy below 500 MeV/nucleon induce less than 5% of the total effective dose behind shielding. This is an important finding since GCR model development and validation have been heavily biased toward Advanced Composition Explorer/Cosmic Ray Isotope Spectrometer measurements below 500 MeV/nucleon. Weights were also developed that quantify the relative contribution of defined GCR energy and charge groups to effective dose behind shielding. In the second paper, it was shown that these weights could be used to efficiently propagate GCR model uncertainties into effective dose behind shielding. In this work, uncertainties are quantified for a few commonly used GCR models. A validation metric is developed that accounts for measurements uncertainty, and the metric is coupled to the fast uncertainty propagation method. For this work, the Badhwar-O'Neill (BON) 2010 and 2011 and the Matthia GCR models are compared to an extensive measurement database. It is shown that BON2011 systematically overestimates heavy ion fluxes in the range 0.5-4 GeV/nucleon. The BON2010 and BON2011 also show moderate and large errors in reproducing past solar activity near the 2000 solar maximum and 2010 solar minimum. It is found that all three models induce relative errors in effective dose in the interval [-20%, 20%] at a 68% confidence level. The BON2010 and Matthia models are found to have similar overall uncertainty estimates and are preferred for space radiation shielding applications.
Determination of effective loss factors in reduced SEA models
Chimeno Manguán, M.; Fernández de las Heras, M. J.; Roibás Millán, E.; Simón Hidalgo, F.
2017-01-01
The definition of Statistical Energy Analysis (SEA) models for large complex structures is highly conditioned by the classification of the structure elements into a set of coupled subsystems and the subsequent determination of the loss factors representing both the internal damping and the coupling between subsystems. The accurate definition of the complete system can lead to excessively large models as the size and complexity increases. This fact can also rise practical issues for the experimental determination of the loss factors. This work presents a formulation of reduced SEA models for incomplete systems defined by a set of effective loss factors. This reduced SEA model provides a feasible number of subsystems for the application of the Power Injection Method (PIM). For structures of high complexity, their components accessibility can be restricted, for instance internal equipments or panels. For these cases the use of PIM to carry out an experimental SEA analysis is not possible. New methods are presented for this case in combination with the reduced SEA models. These methods allow defining some of the model loss factors that could not be obtained through PIM. The methods are validated with a numerical analysis case and they are also applied to an actual spacecraft structure with accessibility restrictions: a solar wing in folded configuration.
An automatic and effective parameter optimization method for model tuning
Directory of Open Access Journals (Sweden)
T. Zhang
2015-05-01
Full Text Available Physical parameterizations in General Circulation Models (GCMs, having various uncertain parameters, greatly impact model performance and model climate sensitivity. Traditional manual and empirical tuning of these parameters is time consuming and ineffective. In this study, a "three-step" methodology is proposed to automatically and effectively obtain the optimum combination of some key parameters in cloud and convective parameterizations according to a comprehensive objective evaluation metrics. Different from the traditional optimization methods, two extra steps, one determines parameter sensitivity and the other chooses the optimum initial value of sensitive parameters, are introduced before the downhill simplex method to reduce the computational cost and improve the tuning performance. Atmospheric GCM simulation results show that the optimum combination of these parameters determined using this method is able to improve the model's overall performance by 9%. The proposed methodology and software framework can be easily applied to other GCMs to speed up the model development process, especially regarding unavoidable comprehensive parameters tuning during the model development stage.
Effects of random noise in a dynamical model of love
Energy Technology Data Exchange (ETDEWEB)
Xu Yong, E-mail: hsux3@nwpu.edu.cn [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China); Gu Rencai; Zhang Huiqing [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)
2011-07-15
Highlights: > We model the complexity and unpredictability of psychology as Gaussian white noise. > The stochastic system of love is considered including bifurcation and chaos. > We show that noise can both suppress and induce chaos in dynamical models of love. - Abstract: This paper aims to investigate the stochastic model of love and the effects of random noise. We first revisit the deterministic model of love and some basic properties are presented such as: symmetry, dissipation, fixed points (equilibrium), chaotic behaviors and chaotic attractors. Then we construct a stochastic love-triangle model with parametric random excitation due to the complexity and unpredictability of the psychological system, where the randomness is modeled as the standard Gaussian noise. Stochastic dynamics under different three cases of 'Romeo's romantic style', are examined and two kinds of bifurcations versus the noise intensity parameter are observed by the criteria of changes of top Lyapunov exponent and shape of stationary probability density function (PDF) respectively. The phase portraits and time history are carried out to verify the proposed results, and the good agreement can be found. And also the dual roles of the random noise, namely suppressing and inducing chaos are revealed.
Ecotoxicity Effect Indicator for use in the OMNIITOX Base Model
DEFF Research Database (Denmark)
Larsen, Henrik Fred; Payet, Jerome; Molander, S
2004-01-01
for the estimation of the EFI. However none of these methods are found to be adequately robust and/or able to work on the low data input defined by the OMNIITOX Base Model (BM), i.e. a minimum of three acute EC50 values. Given the fact that the BM should be applicable to a significant number of chemicals......, this requirement follows from the current and the most likely future data availability as defined by the proposed EU chemicals policy REACH. In this paper, a theoretical elaboration of effect-based average approaches (arithmetic mean, geometric mean and median) and the non-effect based approach (PNEC) is made...... focusing on their statistical robustness. Considerations about the possibility to relate the effect indicator to damage on the endpoint, the ecosystem, are also included. The effect-based approaches are tested for their robustness in estimating an HC50 in a practical test on datasets from eleven different...
The effect of risk-taking behaviour in epidemic models.
Sega, L; Maxin, D; Eaton, L; Latham, A; Moose, A; Stenslie, S
2015-01-01
We study an epidemic model that incorporates risk-taking behaviour as a response to a perceived low prevalence of infection that follows from the administration of an effective treatment or vaccine. We assume that knowledge about the number of infected, recovered and vaccinated individuals has an effect in the contact rate between susceptible and infectious individuals. We show that, whenever optimism prevails in the risk behaviour response, the fate of an epidemic may change from disease clearance to disease persistence. Moreover, under certain conditions on the parameters, increasing the efficiency of vaccine and/or treatment has the unwanted effect of increasing the epidemic reproductive number, suggesting a wider range of diseases may become endemic due to risk-taking alone. These results indicate that the manner in which treatment/vaccine effectiveness is advertised can have an important influence on how the epidemic unfolds.
Effects of model schematisation, geometry and parameter values on urban flood modelling.
Vojinovic, Z; Seyoum, S D; Mwalwaka, J M; Price, R K
2011-01-01
One-dimensional (1D) hydrodynamic models have been used as a standard industry practice for urban flood modelling work for many years. More recently, however, model formulations have included a 1D representation of the main channels and a 2D representation of the floodplains. Since the physical process of describing exchanges of flows with the floodplains can be represented in different ways, the predictive capability of different modelling approaches can also vary. The present paper explores effects of some of the issues that concern urban flood modelling work. Impacts from applying different model schematisation, geometry and parameter values were investigated. The study has mainly focussed on exploring how different Digital Terrain Model (DTM) resolution, presence of different features on DTM such as roads and building structures and different friction coefficients affect the simulation results. Practical implications of these issues are analysed and illustrated in a case study from St Maarten, N.A. The results from this study aim to provide users of numerical models with information that can be used in the analyses of flooding processes in urban areas.
Integrated hydrologic modeling: Effects of spatial scale, discretization and initialization
Seck, A.; Welty, C.; Maxwell, R. M.
2011-12-01
Groundwater discharge contributes significantly to the annual flows of Chesapeake Bay tributaries and is presumed to contribute to the observed lag time between the implementation of management actions and the environmental response in the Chesapeake Bay. To investigate groundwater fluxes and flow paths and interaction with surface flow, we have developed a fully distributed integrated hydrologic model of the Chesapeake Bay Watershed using ParFlow. Here we present a comparison of model spatial resolution and initialization methods. We have studied the effect of horizontal discretization on overland flow processes at a range of scales. Three nested model domains have been considered: the Monocacy watershed (5600 sq. km), the Potomac watershed (92000 sq. km) and the Chesapeake Bay watershed (400,000 sq. km). Models with homogeneous subsurface and topographically-derived slopes were evaluated at 500-m, 1000-m, 2000-m, and 4000-m grid resolutions. Land surface slopes were derived from resampled DEMs and corrected using stream networks. Simulation results show that the overland flow processes are reasonably well represented with a resolution up to 2000 m. We observe that the effects of horizontal resolution dissipate with larger scale models. Using a homogeneous model that includes subsurface and surface terrain characteristics, we have evaluated various initialization methods for the integrated Monocacy watershed model. This model used several options for water table depths and two rainfall forcing methods including (1) a synthetic rainfall-recession cycle corresponding to the region's average annual rainfall rate, and (2) an initial shut-off of rainfall forcing followed by a rainfall-recession cycling. Results show the dominance of groundwater generated runoff during a first phase of the simulation followed by a convergence towards more balanced runoff generation mechanisms. We observe that the influence of groundwater runoff increases in dissected relief areas
Kim, Young-Suk Grace; Schatschneider, Christopher
2017-01-01
We investigated direct and indirect effects of component skills on writing (DIEW) using data from 193 children in Grade 1. In this model, working memory was hypothesized to be a foundational cognitive ability for language and cognitive skills as well as transcription skills, which, in turn, contribute to writing. Foundational oral language skills (vocabulary and grammatical knowledge) and higher-order cognitive skills (inference and theory of mind) were hypothesized to be component skills of text generation (i.e., discourse-level oral language). Results from structural equation modeling largely supported a complete mediation model among four variations of the DIEW model. Discourse-level oral language, spelling, and handwriting fluency completely mediated the relations of higher-order cognitive skills, foundational oral language, and working memory to writing. Moreover, language and cognitive skills had both direct and indirect relations to discourse-level oral language. Total effects, including direct and indirect effects, were substantial for discourse-level oral language (.46), working memory (.43), and spelling (.37), followed by vocabulary (.19), handwriting (.17), theory of mind (.12), inference (.10), and grammatical knowledge (.10). The model explained approximately 67% of variance in writing quality. These results indicate that multiple language and cognitive skills make direct and indirect contributions, and it is important to consider both direct and indirect pathways of influences when considering skills that are important to writing.
Optics of an opal modeled with a stratified effective index and the effect of the interface
Maurin, Isabelle; Laliotis, Athanasios; Bloch, Daniel
2015-01-01
Reflection and transmission for an artificial opal are described through a model of stratified medium based upon a one-dimensional variation of an effective index. The model is notably applicable to a Langmuir-Blodgett type disordered opal. Light scattering is accounted for by a phenomenological absorption. The interface region between the opal and the substrate -or the vacuum- induces a periodicity break in the photonic crystal arrangement, which exhibits a prominent influence on the reflection, notably away from the Bragg reflection peak. Experimental results are compared to our model. The model is extendable to inverse opals, stacked cylinders, or irradiation by evanescent waves
Model of flicker noise effects on phase noise in oscillators
Centurelli, Francesco; Ercolani, Alessandro; Tommasino, Pasquale; Trifiletti, Alessandro
2003-05-01
Phase noise models that describe the near-carrier spectrum in an accurate but insightful way are needed, to better optimize the oscillator design. In this paper we present a model to describe the effect of flicker noise sources on the phase noise of an oscillator, that can be applied both to linear oscillators and to nonlinear structures like relaxation and ring oscillators, so extending previous works that considered only the effect of the flicker noise superimposed to the control voltage of a VCO. In the phase noise of an oscillator we can separate the effect of high frequency noise sources, that can be described by a short-time-constant system, and the effect of low frequency noises (mostly flicker sources), described by a system with time constants much slower than the oscillation period. Flicker noise has been considered to cause a change in the circuit bias point; this bias point change can be mapped in a shift of the oscillation frequency by exploiting Barkhausen conditions (for linear oscillators) or obtaining this link by simulations. The power spectral density of the oscillator can then be obtained as the probability distribution of the oscillation frequency, starting from the flicker noise probability distribution. If the effect of high frequency noise sources is also taken into account, the overall oscillator spectrum can be obtained as a convolution of the spectrum due to flicker sources with the Lorentzian-shaped spectrum due to white noise sources, in analogy with the description of inhomogeneous broadening of laser linewidth.
Towards Effective Elicitation of NIN-AND Tree Causal Models
Xiang, Yang; Li, Yu; Zhu, Zoe Jingyu
To specify a Bayes net (BN), a conditional probability table (CPT), often of an effect conditioned on its n causes, needs assessed for each node. It generally has the complexity exponential on n. Noisy-OR reduces the complexity to linear, but can only represent reinforcing causal interactions. The non-impeding noisy-AND (NIN-AND) tree is the first causal model that explicitly expresses reinforcement, undermining, and their mixture. It has linear complexity, but requires elicitation of a tree topology for types of causal interactions. We study their topology space and develop two novel techniques for more effective elicitation.
Schwinger effect and negative differential conductivity in holographic models
Directory of Open Access Journals (Sweden)
Shankhadeep Chakrabortty
2015-01-01
Full Text Available The consequences of the Schwinger effect for conductivity are computed for strong coupling systems using holography. The one-loop diagram on the flavor brane introduces an O(λNc imaginary part in the effective action for a Maxwell flavor gauge field. This in turn introduces a real conductivity in an otherwise insulating phase of the boundary theory. Moreover, in certain regions of parameter space the differential conductivity is negative. This is computed in the context of the Sakai–Sugimoto model.
Modeling of Atmospheric Turbulence Effect on Terrestrial FSO Link
Directory of Open Access Journals (Sweden)
A. Prokes
2009-04-01
Full Text Available Atmospheric turbulence results in many effects causing fluctuation in the received optical power. Terrestrial laser beam communication is affected above all by scintillations. The paper deals with modeling the influence of scintillation on link performance, using the modified Rytov theory. The probability of correct signal detection in direct detection system in dependence on many parameters such as link distance, power link margin, refractive-index structure parameter, etc. is discussed and different approaches to the evaluation of scintillation effect are compared. The simulations are performed for a horizontal-path propagation of the Gaussian-beam wave.
Modeling magnetized star-planet interactions: boundary conditions effects
Strugarek, Antoine; Matt, Sean P; Reville, Victor
2013-01-01
We model the magnetized interaction between a star and a close-in planet (SPMIs), using global, magnetohydrodynamic numerical simulations. In this proceedings, we study the effects of the numerical boundary conditions at the stellar surface, where the stellar wind is driven, and in the planetary interior. We show that is it possible to design boundary conditions that are adequate to obtain physically realistic, steady-state solutions for cases with both magnetized and unmagnetized planets. This encourages further development of numerical studies, in order to better constrain and understand SPMIs, as well as their effects on the star-planet rotational evolution.
The Effects of Voyaging on the Magnetization of Ship Models.
1980-05-05
time-effect must be analyzed for more accurate prediction of voyage effects. Finally, experiments must be conducted with samples of HY80 steel , for...models were tested by subjecting two sample rods, one of HY1O0 steel and one of HY130 steel to an apparatus for supply of cyclic stress of two amplitudes...Entered) WI UNCLASSIFIED I SECURITY CLASSIFICATION Of T"IS PAGE (Whm Da ffIfete 0. 0.CONTIN(UMD steel , and these were compared with the slope of the
Kim, Young-Suk Grace; Schatschneider, Christopher
2017-01-01
We investigated direct and indirect effects of component skills on writing (DIEW) using data from 193 children in Grade 1. In this model, working memory was hypothesized to be a foundational cognitive ability for language and cognitive skills as well as transcription skills, which, in turn, contribute to writing. Foundational oral language skills…
Kim, Young-Suk Grace; Schatschneider, Christopher
2017-01-01
We investigated direct and indirect effects of component skills on writing (DIEW) using data from 193 children in Grade 1. In this model, working memory was hypothesized to be a foundational cognitive ability for language and cognitive skills as well as transcription skills, which, in turn, contribute to writing. Foundational oral language skills…
The effects of model and data complexity on predictions from species distributions models
DEFF Research Database (Denmark)
García-Callejas, David; Bastos, Miguel
2016-01-01
study contradicts the widely held view that the complexity of species distributions models has significant effects in their predictive ability while findings support for previous observations that the properties of species distributions data and their relationship with the environment are strong...
Effects of garlicin on apoptosis in rat model of colitis
Institute of Scientific and Technical Information of China (English)
Xi-Ming Xu; Jie-Ping Yu; Xiao-Fei He; Jun-Hua Li; Liang-Liang Yu; Hong-Gang Yu
2005-01-01
AIM: To investigate the effects of garlicin on apoptosis and expression of bcl-2 and bax in lymphocytes in rat model of ulcerative colitis (UC).METHODS: Healthy adult Sprague-Dawley rats of both sexes, weighing 180±30 g, were employed in the present study. The rat model of UC was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) enema. The experimental animals were randomly divided into garlicin treatment group (including high and low concentration), model control group, and normal control group. Rats in garlicin treatment group and model control group received intracolic garlicin daily at doses of 10.0 and 30.0 mg/kg and equal amount of saline respectively 24 h after colitis model was induced by alcohol and TNBS co-enema. Rats in normal control group received neither alcohol nor only TNBS but only saline enema in this study. On the 28th d of the experiment, rats were executed, the expression of bcl-2 and bax protein was determined immunohistochemically and the apoptotic cells were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate fluorescence nick end labeling (TUNEL) method. At the same time, the rat colon mucosal damage index (CMDI) was calculated.RESULTS: In garlicin treatment group, the positive expression of bcl-2 in lymphocytes decreased and the number of apoptotic cells was more than that in model control group, CMDI was lower than that in model control group. The positive expression of bax in lymphocytes had no significant difference.CONCLUSION: Garlicin can protect colonic mucosa against damage in rat model of UC induced by TNBS enema.
Modeling of biological doses and mechanical effects on bone transduction
Rieger, Romain; Jennane, Rachid; 10.1016/j.jtbi.2011.01.003
2012-01-01
Shear stress, hormones like parathyroid and mineral elements like calcium mediate the amplitude of stimulus signal which affects the rate of bone remodeling. The current study investigates the theoretical effects of different metabolic doses in stimulus signal level on bone. The model was built considering the osteocyte as the sensing center mediated by coupled mechanical shear stress and some biological factors. The proposed enhanced model was developed based on previously published works dealing with different aspects of bone transduction. It describes the effects of physiological doses variations of Calcium, Parathyroid Hormone, Nitric Oxide and Prostaglandin E2 on the stimulus level sensed by osteocytes in response to applied shear stress generated by interstitial fluid flow. We retained the metabolic factors (Parathyroid Hormone, Nitric Oxide, and Prostaglandin E2) as parameters of bone cell mechanosensitivity because stimulation/inhibition of induced pathways stimulates osteogenic response in vivo. We t...
Applying learning theories and instructional design models for effective instruction.
Khalil, Mohammed K; Elkhider, Ihsan A
2016-06-01
Faculty members in higher education are involved in many instructional design activities without formal training in learning theories and the science of instruction. Learning theories provide the foundation for the selection of instructional strategies and allow for reliable prediction of their effectiveness. To achieve effective learning outcomes, the science of instruction and instructional design models are used to guide the development of instructional design strategies that elicit appropriate cognitive processes. Here, the major learning theories are discussed and selected examples of instructional design models are explained. The main objective of this article is to present the science of learning and instruction as theoretical evidence for the design and delivery of instructional materials. In addition, this article provides a practical framework for implementing those theories in the classroom and laboratory. Copyright © 2016 The American Physiological Society.
Effective Actions of IIB Matrix Model on S^3
Kaneko, Hiromichi; Matsumoto, Koichiro
2007-01-01
S^3 is a simple principle bundle which is locally S^2 \\times S^1. It has been shown that such a space can be constructed in terms of matrix models. It has been also shown that such a space can be realized by a generalized compactification procedure in the S^1 direction. We investigate the effective action of supersymmetric gauge theory on S^3 with an angular momentum cutoff and that of a matrix model compactification. The both cases can be realized in a deformed IIB matrix model with a Myers Term. We find that the highly divergent contributions at the tree and one loop level are sensitive to the uv cutoff. However the two loop level contributions are universal since they are only logarithmically divergent. We expect that the higher loop contributions are insensitive to the uv cutoff since 3d gauge theory is super renormalizable.
Study of Purchase Process Modeling and Reengineering Effects Evaluation
Institute of Scientific and Technical Information of China (English)
ZhenhuanJiang; LiangQuan; PeiwuDong
2004-01-01
Purchase process is an important part in the process of running an enterprise.For reengineering the process of'enterprise, raise business efficiency of enterprise , make enterprise competitive among complicated and changeable market environment. Use the method of planning to evaluate the technology modeling and method to set up evaluation index, based on the basic principle business process reengineering, studied the methods of modeling and evaluating of the reengineering of the purchase process. Given the intact method of modeling process. Give the mathematics express method and figure express method of the process, propose using PT reducing rate to evaluate the effect of the process reengineer, and has analysed three kinds of situations that affect the reducing rate of PT.
Model instruments of effective segmentation of the fast food market
Directory of Open Access Journals (Sweden)
Mityaeva Tetyana L.
2013-03-01
Full Text Available The article presents results of optimisation step-type calculations of economic effectiveness of promotion of fast food with consideration of key parameters of assessment of efficiency of the marketing strategy of segmentation. The article justifies development of a mathematical model on the bases of 3D-presentations and three-dimensional system of management variables. The modern applied mathematical packages allow formation not only of one-dimensional and two-dimensional arrays and analyse links of variables, but also of three-dimensional, besides, the more links and parameters are taken into account, the more adequate and adaptive are results of modelling and, as a result, more informative and strategically valuable. The article shows modelling possibilities that allow taking into account strategies and reactions on formation of the marketing strategy under conditions of entering the fast food market segments.
Modeling the Effects of Mergers in the Retail Sector
DEFF Research Database (Denmark)
Blomgren-Hansen, Niels
2013-01-01
the retail and wholesale markets is constructed, calibrated and simulated based on a concrete case (the acquisition and merger of 250 shops previously organized in a voluntary chain of shops comprising roughly half of the market for high-end cosmetics in Denmark). Model simulations predicts that the merger......According to EU competition law, mergers that significantly impedes effective competition, particularly by creating or strengthening a dominant position are prohibited. To identify these cases, authorities need a quantifiable model of the relationship between the variables that are affected...... by the merger and some measure of competition. Furthermore, the authorities must make their decision quickly, rendering deliberate data collection and econometric analyses infeasible in practice. The decision must be based on easily accessible data. In this paper, a simple model of the interaction between...
Effective-one-body modeling of precessing black hole binaries
Taracchini, Andrea; Babak, Stanislav; Buonanno, Alessandra
2016-03-01
Merging black hole binaries with generic spins that undergo precessional motion emit complicated gravitational-wave signals. We discuss how such waveforms can be accurately modeled within an effective-one-body approach by (i) exploiting the simplicity of the signals in a frame that corotates with the orbital plane of the binary and (ii) relying on an accurate model of nonprecessing black hole binaries. The model is validated by extensive comparisons to 70 numerical relativity simulations of precessing black hole binaries and can generate inspiral-merger-ringdown waveforms for mass ratios up to 100 and any spin configuration. This work is an essential tool for studying and characterizing candidate gravitational-wave events in science runs of advanced LIGO.
Modeling Distortion Effects in Class-D Amplifier Filter Inductors
DEFF Research Database (Denmark)
Knott, Arnold; Stegenborg-Andersen, Tore; Thomsen, Ole Cornelius
2010-01-01
Distortion is generally accepted as a quantifier to judge the quality of audio power amplifiers. In switchmode power amplifiers various mechanisms influence this performance measure. After giving an overview of those, this paper focuses on the particular effect of the nonlinearity of the output...... filter components on the audio performance. While the physical reasons for both, the capacitor and the inductor induced distortion are given, the practical in depth demonstration is done for the inductor only. This includes measuring the inductors performance, modeling through fitting and resulting...... into simulation models. The fitted models achieve distortion values between 0.03 % and 0.2 % as a basis to enable the design of a 200 W amplifier....
Modeling Strain Rate Effect for Heterogeneous Brittle Materials
Institute of Scientific and Technical Information of China (English)
MA Guowei; DONG Aiai; LI Jianchun
2006-01-01
Rocks are heterogeneous from the point of microstructure which is of significance to their dynamic failure behavior.Both the compressive and tensile strength of rock-like materials is regarded different from the static strength.The present study adopts smoothed particle hydrodynamics (SPH) which is a virtual particle based meshfree method to investigate strain rate effect for heterogeneous brittle materials.The SPH method is capable of simulating rock fracture,free of the mesh constraint of the traditional FEM and FDM models.A pressure dependent J-H constitutive model involving heterogeneity is employed in the numerical modeling.The results show the compressive strength increases with the increase of strain rate as well as the tensile strength,which is important to the engineering design.
Effects of model layer simplification using composite hydraulic properties
Kuniansky, Eve L.; Sepulveda, Nicasio; Elango, Lakshmanan
2011-01-01
Groundwater provides much of the fresh drinking water to more than 1.5 billion people in the world (Clarke et al., 1996) and in the United States more that 50 percent of citizens rely on groundwater for drinking water (Solley et al., 1998). As aquifer systems are developed for water supply, the hydrologic system is changed. Water pumped from the aquifer system initially can come from some combination of inducing more recharge, water permanently removed from storage, and decreased groundwater discharge. Once a new equilibrium is achieved, all of the pumpage must come from induced recharge and decreased discharge (Alley et al., 1999). Further development of groundwater resources may result in reductions of surface water runoff and base flows. Competing demands for groundwater resources require good management. Adequate data to characterize the aquifers and confining units of the system, like hydrologic boundaries, groundwater levels, streamflow, and groundwater pumping and climatic data for recharge estimation are to be collected in order to quantify the effects of groundwater withdrawals on wetlands, streams, and lakes. Once collected, three-dimensional (3D) groundwater flow models can be developed and calibrated and used as a tool for groundwater management. The main hydraulic parameters that comprise a regional or subregional model of an aquifer system are the hydraulic conductivity and storage properties of the aquifers and confining units (hydrogeologic units) that confine the system. Many 3D groundwater flow models used to help assess groundwater/surface-water interactions require calculating ?effective? or composite hydraulic properties of multilayered lithologic units within a hydrogeologic unit. The calculation of composite hydraulic properties stems from the need to characterize groundwater flow using coarse model layering in order to reduce simulation times while still representing the flow through the system accurately. The accuracy of flow models with
Institute of Scientific and Technical Information of China (English)
WANG San-de; YANG De-sen; LIU Ning
2007-01-01
In this paper, the acoustic scale effects and boundary effects for the similitude model of underwater complex shell-structure are investigated. The similitude conditions and relations between the similitude model and its prototype were studied in the references This paper investigates the acoustic scale effects for the similitude model, which are influenced by loss factor, shear and rotatory inertia. At the same time, the boundary effects which are influenced by surface sound reflection are investigated in the experiment of similitude model. The results show that the acoustic scale effects may be controlled with model designing, the boundary effects can be controlled with experimental designing between the similitude model and its prototype.
Estimating the Effects of Parental Divorce and Death With Fixed Effects Models
Amato, Paul R.; Anthony, Christopher J.
2014-01-01
The authors used child fixed effects models to estimate the effects of parental divorce and death on a variety of outcomes using 2 large national data sets: (a) the Early Childhood Longitudinal Study, Kindergarten Cohort (kindergarten through the 5th grade) and (b) the National Educational Longitudinal Study (8th grade to the senior year of high school). In both data sets, divorce and death were associated with multiple negative outcomes among children. Although evidence for a causal effect o...
Treatment of cloud radiative effects in general circulation models
Energy Technology Data Exchange (ETDEWEB)
Wang, W.C.; Dudek, M.P.; Liang, X.Z.; Ding, M. [State Univ. of New York, Albany, NY (United States)] [and others
1996-04-01
We participate in the Atmospheric Radiation Measurement (ARM) program with two objectives: (1) to improve the general circulation model (GCM) cloud/radiation treatment with a focus on cloud verticle overlapping and layer cloud optical properties, and (2) to study the effects of cloud/radiation-climate interaction on GCM climate simulations. This report summarizes the project progress since the Fourth ARM Science Team meeting February 28-March 4, 1994, in Charleston, South Carolina.
Note on the butterfly effect in holographic superconductor models
Ling, Yi; Wu, Jian-Pin
2016-01-01
In this note we remark that the butterfly effect can be used to diagnose the phase transition of superconductivity in a holographic framework. Specifically, we compute the butterfly velocity in a charged black hole background as well as anisotropic backgrounds with Q-lattice structure. In both cases we find its derivative to the temperature is discontinuous at critical points. We also propose that the butterfly velocity can signalize the occurrence of thermal phase transition in general holographic models.
PGO models in the envelope function and effective mass approximations
Paulescu, M.; Tulcan-Paulescu, E.; Gravila, P.
2011-03-01
A recipe to design quantum devices that exhibit the theoretical pseudo-Gaussian oscillator electronic states properties is given. The algorithm is described en detail and is illustrated by the computation of a Mn x Cd1- x Te ternary alloy pseudo-Gaussian heterostructure. The numerical procedure reaches beyond of pseudo-Gaussian models and can be used for designing epitaxial growth devices with desired electronic states structure. The calculations are carried out in the envelope function and effective mass approximations.
A neural network model of ventriloquism effect and aftereffect.
Directory of Open Access Journals (Sweden)
Elisa Magosso
Full Text Available Presenting simultaneous but spatially discrepant visual and auditory stimuli induces a perceptual translocation of the sound towards the visual input, the ventriloquism effect. General explanation is that vision tends to dominate over audition because of its higher spatial reliability. The underlying neural mechanisms remain unclear. We address this question via a biologically inspired neural network. The model contains two layers of unimodal visual and auditory neurons, with visual neurons having higher spatial resolution than auditory ones. Neurons within each layer communicate via lateral intra-layer synapses; neurons across layers are connected via inter-layer connections. The network accounts for the ventriloquism effect, ascribing it to a positive feedback between the visual and auditory neurons, triggered by residual auditory activity at the position of the visual stimulus. Main results are: i the less localized stimulus is strongly biased toward the most localized stimulus and not vice versa; ii amount of the ventriloquism effect changes with visual-auditory spatial disparity; iii ventriloquism is a robust behavior of the network with respect to parameter value changes. Moreover, the model implements Hebbian rules for potentiation and depression of lateral synapses, to explain ventriloquism aftereffect (that is, the enduring sound shift after exposure to spatially disparate audio-visual stimuli. By adaptively changing the weights of lateral synapses during cross-modal stimulation, the model produces post-adaptive shifts of auditory localization that agree with in-vivo observations. The model demonstrates that two unimodal layers reciprocally interconnected may explain ventriloquism effect and aftereffect, even without the presence of any convergent multimodal area. The proposed study may provide advancement in understanding neural architecture and mechanisms at the basis of visual-auditory integration in the spatial realm.
Effects of seasonal growth on delayed prey-predator model
Energy Technology Data Exchange (ETDEWEB)
Gakkhar, Sunita [Department of Mathematics, IIT Roorkee, Roorkee 247667 (India)], E-mail: sungkfma@iitr.ernet.in; Sahani, Saroj Kumar [Department of Mathematics, IIT Roorkee, Roorkee 247667 (India)], E-mail: sarojdma@iitr.ernet.in; Negi, Kuldeep [Department of Mathematics, IIT Roorkee, Roorkee 247667 (India)], E-mail: negikdma@iitr.ernet.in
2009-01-15
The dynamic behavior of a delayed predator-prey system with Holling II functional response is investigated. The stability analysis has been carried out and existence of Hopf bifurcation has been established. The complex dynamic behavior due to time delay has been explored. The effects of seasonal growth on the complex dynamics have been simulated. The model shows a rich variety of behavior, including period doubling, quasi-periodicity, chaos, transient chaos, and windows of periodicity.
Note on the butterfly effect in holographic superconductor models
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Yi Ling
2017-05-01
Full Text Available In this note we remark that the butterfly effect can be used to diagnose the phase transition of superconductivity in a holographic framework. Specifically, we compute the butterfly velocity in a charged black hole background as well as anisotropic backgrounds with Q-lattice structure. In both cases we find its derivative to the temperature is discontinuous at critical points. We also propose that the butterfly velocity can signalize the occurrence of thermal phase transition in general holographic models.
Note on the butterfly effect in holographic superconductor models
Ling, Yi; Liu, Peng; Wu, Jian-Pin
2017-05-01
In this note we remark that the butterfly effect can be used to diagnose the phase transition of superconductivity in a holographic framework. Specifically, we compute the butterfly velocity in a charged black hole background as well as anisotropic backgrounds with Q-lattice structure. In both cases we find its derivative to the temperature is discontinuous at critical points. We also propose that the butterfly velocity can signalize the occurrence of thermal phase transition in general holographic models.
Probabilistic Modeling of Intracranial Pressure Effects on Optic Nerve Biomechanics
Ethier, C. R.; Feola, Andrew J.; Raykin, Julia; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.
2016-01-01
Altered intracranial pressure (ICP) is involved/implicated in several ocular conditions: papilledema, glaucoma and Visual Impairment and Intracranial Pressure (VIIP) syndrome. The biomechanical effects of altered ICP on optic nerve head (ONH) tissues in these conditions are uncertain but likely important. We have quantified ICP-induced deformations of ONH tissues, using finite element (FE) and probabilistic modeling (Latin Hypercube Simulations (LHS)) to consider a range of tissue properties and relevant pressures.
Modeling elephant-mediated cascading effects of water point closure.
Hilbers, Jelle P; Van Langevelde, Frank; Prins, Herbert H T; Grant, C C; Peel, Mike J S; Coughenour, Michael B; De Knegt, Henrik J; Slotow, Rob; Smit, Izak P J; Kiker, Greg A; De Boer, Willem F
2015-03-01
Wildlife management to reduce the impact of wildlife on their habitat can be done in several ways, among which removing animals (by either culling or translocation) is most often used. There are, however, alternative ways to control wildlife densities, such as opening or closing water points. The effects of these alternatives are poorly studied. In this paper, we focus on manipulating large herbivores through the closure of water points (WPs). Removal of artificial WPs has been suggested in order to change the distribution of African elephants, which occur in high densities in national parks in Southern Africa and are thought to have a destructive effect on the vegetation. Here, we modeled the long-term effects of different scenarios of WP closure on the spatial distribution of elephants, and consequential effects on the vegetation and other herbivores in Kruger National Park, South Africa. Using a dynamic ecosystem model, SAVANNA, scenarios were evaluated that varied in availability of artificial WPs; levels of natural water; and elephant densities. Our modeling results showed that elephants can indirectly negatively affect the distributions of meso-mixed feeders, meso-browsers, and some meso-grazers under wet conditions. The closure of artificial WPs hardly had any effect during these natural wet conditions. Under dry conditions, the spatial distribution of both elephant bulls and cows changed when the availability of artificial water was severely reduced in the model. These changes in spatial distribution triggered changes in the spatial availability of woody biomass over the simulation period of 80 years, and this led to changes in the rest of the herbivore community, resulting in increased densities of all herbivores, except for giraffe and steenbok, in areas close to rivers. The spatial distributions of elephant bulls and cows showed to be less affected by the closure of WPs than most of the other herbivore species. Our study contributes to ecologically
Symmetry Energy Effects in a Statistical Multifragmentation Model
Institute of Scientific and Technical Information of China (English)
ZHANG Lei; GAO Yuan1; ZHANG Hong-Fei; CHEN Xi-Meng; Yu Mei-Ling; LI Jun-Qing
2011-01-01
The symmetry energy effects on the nuclear disintegration mechanisms of the neutron-rich system (A0 = 200, Z0 = 78) are studied in the framework of the statistical multifragmentation model (SMM) within its micro-canonical ensemble. A modified symmetry energy term with consideration of the volume and surface asymmetry is adopted instead of the original invariable value in the standard SMM model. The results indicate that as the volume and surface asymmetries are considered, the neutron-rich system translates to a fission-like process from evaporation earlier than the original standard SMM model at lower excitation energies, and its mass distribution has larger probabilities in the medium-heavy nuclei range so that the system breaks up more averagely. When the excitation energy becomes higher, the volume and surface asymmetry lead to a smaller average multiplicity.%The symmetry energy effects on the nuclear disintegration mechanisms of the neutron-rich system (A0 =200,Z0 =78) are studied in the framework of the statistical multifragmentation model (SMM) within its micro-canonical ensemble.A modified symmetry energy term with consideration of the volume and surface asymmetry is adopted instead of the original invariable value in the standard SMM model.The results indicate that as the volume and surface asymmetries are considered,the neutron-rich system translates to a fission-like process from evaporation earlier than the original standard SMM model at lower excitation energies,and its mass distribution has larger probabilities in the medium-heavy nuclei range so that the system breaks up more averagely.When the excitation energy becomes higher,the volume and surface asymmetry lead to a smaller average multiplicity.
Modeling the effects of developmental variation on insect phenology.
Yurk, Brian P; Powell, James A
2010-08-01
Phenology, the timing of developmental events such as oviposition or pupation, is highly dependent on temperature; since insects are ectotherms, the time it takes them to complete a life stage (development time) depends on the temperatures they experience. This dependence varies within and between populations due to variation among individuals that is fixed within a life stage (giving rise to what we call persistent variation) and variation from random effects within a life stage (giving rise to what we call random variation). It is important to understand how both types of variation affect phenology if we are to predict the effects of climate change on insect populations.We present three nested phenology models incorporating increasing levels of variation. First, we derive an advection equation to describe the temperature-dependent development of a population with no variation in development time. This model is extended to incorporate persistent variation by introducing a developmental phenotype that varies within a population, yielding a phenotype-dependent advection equation. This is further extended by including a diffusion term describing random variation in a phenotype-dependent Fokker-Planck development equation. These models are also novel because they are formulated in terms of development time rather than developmental rate; development time can be measured directly in the laboratory, whereas developmental rate is calculated by transforming laboratory data. We fit the phenology models to development time data for mountain pine beetles (MPB) (Dendroctonus ponderosae Hopkins [Coleoptera: Scolytidae]) held at constant temperatures in laboratory experiments. The nested models are parameterized using a maximum likelihood approach. The results of the parameterization show that the phenotype-dependent advection model provides the best fit to laboratory data, suggesting that MPB phenology may be adequately described in terms of persistent variation alone. MPB